27578 is a product of 2 and 4k+1 prime and so it can be expressed as a sum of two squares in one way only viz. 107^2 + 127^2.

27578 is a member of OEIS A296812: squarefree semiprimes whose differences lead repeatedly to five other squarefree semiprimes, here 13787, 794, 395, 74 and 35. The sequence can be generated as follows:

INPUT

S=[n for n in [1..40000] if len(prime_factors(n))==2 and len(divisors(n))==4]

L,k=[],5

for n in S:

  count=0

  number=n

  while number in S:

    P=prime_factors(number)

    number=P[1]-P[0]

    count+=1

  if count==k:

    L.append(n)

print(L)

OUTPUT

13787 = 17 * 811

794 = 2 * 397

395 = 5 * 79

74 = 2 * 37

35 = 5 * 7

[4786, 5991, 6218, 8351, 9995, 13391, 15434, 16658, 19466, 27578, 34082, 34187, 37727, 38823]

27578 is a self number because there is not a number n which added to its sum of digits gives 27578.

27578 has an aliquot sequence that does not terminate after 101 steps.