256867720 has 32 divisors (see below), whose sum is σ = 580034520. Its totient is φ = 102376960.

The previous prime is 256867717. The next prime is 256867729. The reversal of 256867720 is 27768652.

It can be written as a sum of positive squares in 4 ways, for example, as 185667876 + 71199844 = 13626^2 + 8438^2 .

It is not an unprimeable number, because it can be changed into a prime (256867729) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 187 + ... + 22666.

Almost surely, 2^256867720 is an apocalyptic number.

256867720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256867720 is an abundant number, since it is smaller than the sum of its proper divisors (323166800).

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

256867720 is a wasteful number, since it uses less digits than its factorization.

256867720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23145 (or 23141 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 43.

The square root of 256867720 is about 16027.0933110156. The cubic root of 256867720 is about 635.6770178163.

The spelling of 256867720 in words is "two hundred fifty-six million, eight hundred sixty-seven thousand, seven hundred twenty".