256525260021 has 12 divisors (see below), whose sum is σ = 370900127520. Its totient is φ = 170849005800.

The previous prime is 256525259971. The next prime is 256525260037. The reversal of 256525260021 is 120062525652.

256525260021 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 25 + 2 + 600 + 21 = 666.

It is not a de Polignac number, because 256525260021 - 2²⁷ = 256391042293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256525260041) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13976505 + ... + 13994846.

It is an arithmetic number, because the mean of its divisors is an integer number (30908343960).

Almost surely, 2^256525260021 is an apocalyptic number.

It is an amenable number.

256525260021 is a deficient number, since it is larger than the sum of its proper divisors (114374867499).

256525260021 is a wasteful number, since it uses less digits than its factorization.

256525260021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27972376 (or 27972373 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

Adding to 256525260021 its reverse (120062525652), we get a palindrome (376587785673).

The spelling of 256525260021 in words is "two hundred fifty-six billion, five hundred twenty-five million, two hundred sixty thousand, twenty-one".