256720923 has 12 divisors (see below), whose sum is σ = 377816400. Its totient is φ = 167917776.

The previous prime is 256720901. The next prime is 256720931. The reversal of 256720923 is 329027652.

256720923 is a `hidden beast` number, since 2 + 567 + 2 + 0 + 92 + 3 = 666.

It is not a de Polignac number, because 256720923 - 2¹⁰ = 256719899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (256720943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 268623 + ... + 269576.

It is an arithmetic number, because the mean of its divisors is an integer number (31484700).

Almost surely, 2^256720923 is an apocalyptic number.

256720923 is a deficient number, since it is larger than the sum of its proper divisors (121095477).

256720923 is a wasteful number, since it uses less digits than its factorization.

256720923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538258 (or 538255 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 256720923 is about 16022.5130051437. The cubic root of 256720923 is about 635.5559006630. Note that the first 3 decimals are identical.

The spelling of 256720923 in words is "two hundred fifty-six million, seven hundred twenty thousand, nine hundred twenty-three".