256794721 has 2 divisors, whose sum is σ = 256794722. Its totient is φ = 256794720.

The previous prime is 256794691. The next prime is 256794737. The reversal of 256794721 is 127497652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 237776400 + 19018321 = 15420^2 + 4361^2 .

It is a cyclic number.

It is not a de Polignac number, because 256794721 - 2¹¹ = 256792673 is a prime.

It is not a weakly prime, because it can be changed into another prime (256794121) 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 as a sum of consecutive naturals, namely, 128397360 + 128397361.

It is an arithmetic number, because the mean of its divisors is an integer number (128397361).

Almost surely, 2^256794721 is an apocalyptic number.

It is an amenable number.

256794721 is a deficient number, since it is larger than the sum of its proper divisors (1).

256794721 is an equidigital number, since it uses as much as digits as its factorization.

256794721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 43.

The square root of 256794721 is about 16024.8157867727. The cubic root of 256794721 is about 635.6167946230.

The spelling of 256794721 in words is "two hundred fifty-six million, seven hundred ninety-four thousand, seven hundred twenty-one".