256832309 has 2 divisors, whose sum is σ = 256832310. Its totient is φ = 256832308.

The previous prime is 256832287. The next prime is 256832321. The reversal of 256832309 is 903238652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256800625 + 31684 = 16025^2 + 178^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256832309 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256832339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128416154 + 128416155.

It is an arithmetic number, because the mean of its divisors is an integer number (128416155).

Almost surely, 2^256832309 is an apocalyptic number.

It is an amenable number.

256832309 is a deficient number, since it is larger than the sum of its proper divisors (1).

256832309 is an equidigital number, since it uses as much as digits as its factorization.

256832309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 38.

The square root of 256832309 is about 16025.9885498524. The cubic root of 256832309 is about 635.6478056427.

The spelling of 256832309 in words is "two hundred fifty-six million, eight hundred thirty-two thousand, three hundred nine".