646955831 has 2 divisors, whose sum is σ = 646955832. Its totient is φ = 646955830.

The previous prime is 646955821. The next prime is 646955887. The reversal of 646955831 is 138559646.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646955831 - 2¹⁸ = 646693687 is a prime.

It is a super-2 number, since 2×646955831² = 837103694529801122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646955821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323477915 + 323477916.

It is an arithmetic number, because the mean of its divisors is an integer number (323477916).

Almost surely, 2^646955831 is an apocalyptic number.

646955831 is a deficient number, since it is larger than the sum of its proper divisors (1).

646955831 is an equidigital number, since it uses as much as digits as its factorization.

646955831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 777600, while the sum is 47.

The square root of 646955831 is about 25435.3264378502. The cubic root of 646955831 is about 864.8846922154.

The spelling of 646955831 in words is "six hundred forty-six million, nine hundred fifty-five thousand, eight hundred thirty-one".