256428440 has 32 divisors (see below), whose sum is σ = 596862000. Its totient is φ = 99033984.

The previous prime is 256428437. The next prime is 256428467. The reversal of 256428440 is 44824652.

It is a self number, because there is not a number n which added to its sum of digits gives 256428440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109370 + ... + 111689.

Almost surely, 2^256428440 is an apocalyptic number.

256428440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256428440 is an abundant number, since it is smaller than the sum of its proper divisors (340433560).

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

256428440 is a wasteful number, since it uses less digits than its factorization.

256428440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221099 (or 221095 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 35.

The square root of 256428440 is about 16013.3831528506. The cubic root of 256428440 is about 635.3144452935.

The spelling of 256428440 in words is "two hundred fifty-six million, four hundred twenty-eight thousand, four hundred forty".