256839406 has 4 divisors (see below), whose sum is σ = 385259112. Its totient is φ = 128419702.

The previous prime is 256839391. The next prime is 256839421. The reversal of 256839406 is 604938652.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (256839391) and next prime (256839421).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64209850 + ... + 64209853.

It is an arithmetic number, because the mean of its divisors is an integer number (96314778).

Almost surely, 2^256839406 is an apocalyptic number.

256839406 is a deficient number, since it is larger than the sum of its proper divisors (128419706).

256839406 is a wasteful number, since it uses less digits than its factorization.

256839406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128419705.

The product of its (nonzero) digits is 311040, while the sum is 43.

The square root of 256839406 is about 16026.2099699211. The cubic root of 256839406 is about 635.6536605017.

The spelling of 256839406 in words is "two hundred fifty-six million, eight hundred thirty-nine thousand, four hundred six".