256573440 has 272 divisors, whose sum is σ = 943711200. Its totient is φ = 66060288.

The previous prime is 256573403. The next prime is 256573451. The reversal of 256573440 is 44375652.

It is a super-2 number, since 2×256573440² = 131659860226867200, which contains 22 as substring.

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 = 256573395 and 256573404.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8847346 + ... + 8847374.

Almost surely, 2^256573440 is an apocalyptic number.

256573440 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 256573440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (471855600).

256573440 is an abundant number, since it is smaller than the sum of its proper divisors (687137760).

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

256573440 is an frugal number, since it uses more digits than its factorization.

256573440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 36.

The square root of 256573440 is about 16017.9099760237. The cubic root of 256573440 is about 635.4341710105.

The spelling of 256573440 in words is "two hundred fifty-six million, five hundred seventy-three thousand, four hundred forty".