256314640 has 20 divisors (see below), whose sum is σ = 595931724. Its totient is φ = 102525824.

The previous prime is 256314629. The next prime is 256314647. The reversal of 256314640 is 46413652.

It can be written as a sum of positive squares in 2 ways, for example, as 98962704 + 157351936 = 9948^2 + 12544^2 .

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

It is not an unprimeable number, because it can be changed into a prime (256314647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1601887 + ... + 1602046.

Almost surely, 2^256314640 is an apocalyptic number.

256314640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256314640 is an abundant number, since it is smaller than the sum of its proper divisors (339617084).

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

256314640 is a wasteful number, since it uses less digits than its factorization.

256314640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3203946 (or 3203940 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 256314640 is about 16009.8294806659. The cubic root of 256314640 is about 635.2204496332.

The spelling of 256314640 in words is "two hundred fifty-six million, three hundred fourteen thousand, six hundred forty".