27573 is a member of OEIS A147619: numbers n = concat(a, b) such that totient(n) = totient(a) * totient(b) , here a=275 and b=73 with totient(275) = 200, totient(73)=72 and totient(27573) = 1440.

The initial members are:

78, 780, 897, 918, 1179, 1365, 1776, 2574, 2598, 2967, 3168, 3762, 4758, 5775, 5796, 7800, 7875, 7917, 8217, 8970, 9180, 9576, 11790, 13650, 13662, 13875, 13896, 14391, 17760, 18564, 18858, 19812, 20097, 25740, 25935, 25974, 25980, 27573, 28776, 28779, 29670, 31680, 33165, 35919, 37620

Note that if n is in this sequence, then n*10 is again in the sequence e.g. 3168 and 31680 in the list above.

Here is an algorithm that will generate all five digit numbers satisfying the condition (permalink):

INPUT

L=[]

T=[("First Part","Second Part","Number")]

T.append(("","",""))

for n in [10000..40000]:

  D=list(str(n))

  if len(D)==5:

    a=int(str(D[0]))

    b=int(str(D[1])+str(D[2])+str(D[3])+str(D[4]))

    c=int(str(D[0])+str(D[1]))

    d=int(str(D[2])+str(D[3])+str(D[4]))

    e=int(str(D[0])+str(D[1])+str(D[2]))

    f=int(str(D[3])+str(D[4]))

    g=int(str(D[0])+str(D[1])+str(D[2])+str(D[3]))

    h=int(str(D[4]))

    if euler_phi(a)*euler_phi(b)==euler_phi(n):

      L.append(n)

      T.append((a,b,n))

    if euler_phi(c)*euler_phi(d)==euler_phi(n):

      L.append(n)

      T.append((c,d,n))

    if euler_phi(e)*euler_phi(f)==euler_phi(n):

      L.append(n)

      T.append((e,f,n))

    if euler_phi(g)*euler_phi(h)==euler_phi(n):

      L.append(n)

      T.append((g,h,n))

print(table(T))

print()

print(sorted(L))

OUTPUT

First Part  Second Part  Number

 11      790      11790

 13      650      13650

 13      662      13662

 13      875      13875

 13      896      13896

 143     91      14391

 17      760      17760

 185     64      18564

 1885     8       18858

 19      812      19812

 2009     7       20097

 25      740      25740

 2593     5       25935

 259     74      25974

 259     80      25980

 275     73      27573

 287     76      28776

 287     79      28779

 29      670      29670

 31      680      31680

 331     65      33165

 35      919      35919

 37      620      37620

[11790, 13650, 13662, 13875, 13896, 14391, 17760, 18564, 18858, 19812, 20097, 25740, 25935, 25974, 25980, 27573, 28776, 28779, 29670, 31680, 33165, 35919, 37620]

27573 is a Curzon number.

27573 can be rendered as a digital equation as follows:

-2 + 7 = -5 + 7 + 3