256809960 has 128 divisors (see below), whose sum is σ = 933897600. Its totient is φ = 62254080.

The previous prime is 256809953. The next prime is 256809977. The reversal of 256809960 is 69908652.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1072 + ... + 22688.

It is an arithmetic number, because the mean of its divisors is an integer number (7296075).

Almost surely, 2^256809960 is an apocalyptic number.

256809960 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 256809960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (466948800).

256809960 is an abundant number, since it is smaller than the sum of its proper divisors (677087640).

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

256809960 is a wasteful number, since it uses less digits than its factorization.

256809960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21648 (or 21638 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 256809960 is about 16025.2912610037. The cubic root of 256809960 is about 635.6293675355.

The spelling of 256809960 in words is "two hundred fifty-six million, eight hundred nine thousand, nine hundred sixty".