256723833734989 has 2 divisors, whose sum is σ = 256723833734990. Its totient is φ = 256723833734988.

The previous prime is 256723833734959. The next prime is 256723833735001. The reversal of 256723833734989 is 989437338327652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 143959610832489 + 112764222902500 = 11998317^2 + 10619050^2 .

It is a cyclic number.

It is not a de Polignac number, because 256723833734989 - 2³⁷ = 256586394781517 is a prime.

It is a super-2 number, since 2×256723833734989² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256723833734909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128361916867494 + 128361916867495.

It is an arithmetic number, because the mean of its divisors is an integer number (128361916867495).

Almost surely, 2^{256723833734989} is an apocalyptic number.

It is an amenable number.

256723833734989 is a deficient number, since it is larger than the sum of its proper divisors (1).

256723833734989 is an equidigital number, since it uses as much as digits as its factorization.

256723833734989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9876142080, while the sum is 79.

The spelling of 256723833734989 in words is "two hundred fifty-six trillion, seven hundred twenty-three billion, eight hundred thirty-three million, seven hundred thirty-four thousand, nine hundred eighty-nine".