256587257522 has 6 divisors (see below), whose sum is σ = 384881960829. Its totient is φ = 128293270580.

The previous prime is 256587257467. The next prime is 256587257539. The reversal of 256587257522 is 225752785652.

It can be written as a sum of positive squares in 2 ways, for example, as 244005372961 + 12581884561 = 493969^2 + 112169^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=358181.

It is a super-2 number, since 2×256587257522² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 537272 + ... + 895452.

Almost surely, 2^256587257522 is an apocalyptic number.

256587257522 is a deficient number, since it is larger than the sum of its proper divisors (128294703307).

256587257522 is an frugal number, since it uses more digits than its factorization.

256587257522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716364 (or 358183 counting only the distinct ones).

The product of its digits is 23520000, while the sum is 56.

The spelling of 256587257522 in words is "two hundred fifty-six billion, five hundred eighty-seven million, two hundred fifty-seven thousand, five hundred twenty-two".