256864140 has 144 divisors (see below), whose sum is σ = 866401536. Its totient is φ = 61171200.

The previous prime is 256864133. The next prime is 256864199. The reversal of 256864140 is 41468652.

256864140 is a `hidden beast` number, since 2 + 5 + 6 + 8 + 641 + 4 + 0 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 256864095 and 256864104.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 70770 + ... + 74310.

Almost surely, 2^256864140 is an apocalyptic number.

256864140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256864140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (433200768).

256864140 is an abundant number, since it is smaller than the sum of its proper divisors (609537396).

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

256864140 is a wasteful number, since it uses less digits than its factorization.

256864140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3600 (or 3595 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 256864140 is about 16026.9816247477. The cubic root of 256864140 is about 635.6740646306.

The spelling of 256864140 in words is "two hundred fifty-six million, eight hundred sixty-four thousand, one hundred forty".