256559440 has 20 divisors (see below), whose sum is σ = 596500884. Its totient is φ = 102623744.

The previous prime is 256559333. The next prime is 256559467. The reversal of 256559440 is 44955652.

It can be written as a sum of positive squares in 2 ways, for example, as 127418944 + 129140496 = 11288^2 + 11364^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×256559440² = 131645492506227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 256559393 and 256559402.

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 3 ways as a sum of consecutive naturals, for example, 1603417 + ... + 1603576.

Almost surely, 2^256559440 is an apocalyptic number.

256559440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256559440 is an abundant number, since it is smaller than the sum of its proper divisors (339941444).

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

256559440 is a wasteful number, since it uses less digits than its factorization.

256559440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3207006 (or 3207000 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 40.

The square root of 256559440 is about 16017.4729592405. The cubic root of 256559440 is about 635.4226132538.

The spelling of 256559440 in words is "two hundred fifty-six million, five hundred fifty-nine thousand, four hundred forty".