256458981940 has 24 divisors (see below), whose sum is σ = 615501556992. Its totient is φ = 87928793760.

The previous prime is 256458981923. The next prime is 256458981949. The reversal of 256458981940 is 49189854652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256458981949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 915924796 + ... + 915925075.

It is an arithmetic number, because the mean of its divisors is an integer number (25645898208).

Almost surely, 2^256458981940 is an apocalyptic number.

256458981940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256458981940 is an abundant number, since it is smaller than the sum of its proper divisors (359042575052).

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

256458981940 is a wasteful number, since it uses less digits than its factorization.

256458981940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1831849887 (or 1831849885 counting only the distinct ones).

The product of its (nonzero) digits is 24883200, while the sum is 61.

The spelling of 256458981940 in words is "two hundred fifty-six billion, four hundred fifty-eight million, nine hundred eighty-one thousand, nine hundred forty".