256635782920 has 32 divisors (see below), whose sum is σ = 629924195520. Its totient is φ = 93322102720.

The previous prime is 256635782863. The next prime is 256635782971. The reversal of 256635782920 is 29287536652.

It is a super-2 number, since 2×256635782920² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291631132 + ... + 291632011.

It is an arithmetic number, because the mean of its divisors is an integer number (19685131110).

Almost surely, 2^256635782920 is an apocalyptic number.

256635782920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256635782920 is an abundant number, since it is smaller than the sum of its proper divisors (373288412600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256635782920 is a wasteful number, since it uses less digits than its factorization.

256635782920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583263165 (or 583263161 counting only the distinct ones).

The product of its (nonzero) digits is 10886400, while the sum is 55.

The spelling of 256635782920 in words is "two hundred fifty-six billion, six hundred thirty-five million, seven hundred eighty-two thousand, nine hundred twenty".