256740856 has 8 divisors (see below), whose sum is σ = 481389120. Its totient is φ = 128370424.

The previous prime is 256740839. The next prime is 256740929. The reversal of 256740856 is 658047652.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×256740856² = 131831734279225472, which contains 22 as substring.

It is a congruent number.

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 as a sum of consecutive naturals, namely, 16046296 + ... + 16046311.

It is an arithmetic number, because the mean of its divisors is an integer number (60173640).

Almost surely, 2^256740856 is an apocalyptic number.

It is an amenable number.

256740856 is a deficient number, since it is larger than the sum of its proper divisors (224648264).

256740856 is a wasteful number, since it uses less digits than its factorization.

256740856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32092613 (or 32092609 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 43.

The square root of 256740856 is about 16023.1350240831. The cubic root of 256740856 is about 635.5723494040.

The spelling of 256740856 in words is "two hundred fifty-six million, seven hundred forty thousand, eight hundred fifty-six".