256508140 has 72 divisors (see below), whose sum is σ = 640059840. Its totient is φ = 86059008.

The previous prime is 256508107. The next prime is 256508171. The reversal of 256508140 is 41805652.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43276 + ... + 48844.

It is an arithmetic number, because the mean of its divisors is an integer number (8889720).

Almost surely, 2^256508140 is an apocalyptic number.

256508140 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 256508140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320029920).

256508140 is an abundant number, since it is smaller than the sum of its proper divisors (383551700).

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

256508140 is a wasteful number, since it uses less digits than its factorization.

256508140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5639 (or 5630 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 256508140 is about 16015.8715029810. The cubic root of 256508140 is about 635.3802587375.

The spelling of 256508140 in words is "two hundred fifty-six million, five hundred eight thousand, one hundred forty".