256587540 has 96 divisors (see below), whose sum is σ = 817883136. Its totient is φ = 59495040.

The previous prime is 256587521. The next prime is 256587547. The reversal of 256587540 is 45785652.

It is a junction number, because it is equal to n+sod(n) for n = 256587492 and 256587501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256587547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6729 + ... + 23631.

It is an arithmetic number, because the mean of its divisors is an integer number (8519616).

Almost surely, 2^256587540 is an apocalyptic number.

256587540 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 256587540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (408941568).

256587540 is an abundant number, since it is smaller than the sum of its proper divisors (561295596).

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

256587540 is a wasteful number, since it uses less digits than its factorization.

256587540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16949 (or 16947 counting only the distinct ones).

The product of its (nonzero) digits is 336000, while the sum is 42.

The square root of 256587540 is about 16018.3501023045. The cubic root of 256587540 is about 635.4458108977.

The spelling of 256587540 in words is "two hundred fifty-six million, five hundred eighty-seven thousand, five hundred forty".