256366909 has 2 divisors, whose sum is σ = 256366910. Its totient is φ = 256366908.

The previous prime is 256366853. The next prime is 256366921. The reversal of 256366909 is 909663652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 239940100 + 16426809 = 15490^2 + 4053^2 .

It is a cyclic number.

It is not a de Polignac number, because 256366909 - 2²³ = 247978301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256366939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128183454 + 128183455.

It is an arithmetic number, because the mean of its divisors is an integer number (128183455).

Almost surely, 2^256366909 is an apocalyptic number.

It is an amenable number.

256366909 is a deficient number, since it is larger than the sum of its proper divisors (1).

256366909 is an equidigital number, since it uses as much as digits as its factorization.

256366909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 524880, while the sum is 46.

The square root of 256366909 is about 16011.4618008475. The cubic root of 256366909 is about 635.2636258391.

The spelling of 256366909 in words is "two hundred fifty-six million, three hundred sixty-six thousand, nine hundred nine".