256431844881 has 81 divisors (see below), whose sum is σ = 399110152987. Its totient is φ = 158642172480.

The previous prime is 256431844859. The next prime is 256431844909. The reversal of 256431844881 is 188448134652.

The square root of 256431844881 is 506391.

It is a perfect power (a square), and thus also a powerful number.

256431844881 is a `hidden beast` number, since 2 + 56 + 4 + 31 + 84 + 488 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12356323281 + 244075521600 = 111159^2 + 494040^2 .

It is not a de Polignac number, because 256431844881 - 2⁹ = 256431844369 is a prime.

It is a super-3 number, since 3×256431844881³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256431844831) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1432580050 + ... + 1432580228.

Almost surely, 2^256431844881 is an apocalyptic number.

256431844881 is the 506391-st square number.

256431844881 is the 253196-th centered octagonal number.

It is an amenable number.

256431844881 is a deficient number, since it is larger than the sum of its proper divisors (142678308106).

256431844881 is an equidigital number, since it uses as much as digits as its factorization.

256431844881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 246 counting only the distinct ones).

The product of its digits is 5898240, while the sum is 54.

The spelling of 256431844881 in words is "two hundred fifty-six billion, four hundred thirty-one million, eight hundred forty-four thousand, eight hundred eighty-one".