644956339 has 2 divisors, whose sum is σ = 644956340. Its totient is φ = 644956338.

The previous prime is 644956321. The next prime is 644956343. The reversal of 644956339 is 933659446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644956339 - 2¹⁷ = 644825267 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 644956292 and 644956301.

It is not a weakly prime, because it can be changed into another prime (644956369) 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, 322478169 + 322478170.

It is an arithmetic number, because the mean of its divisors is an integer number (322478170).

Almost surely, 2^644956339 is an apocalyptic number.

644956339 is a deficient number, since it is larger than the sum of its proper divisors (1).

644956339 is an equidigital number, since it uses as much as digits as its factorization.

644956339 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2099520, while the sum is 49.

The square root of 644956339 is about 25395.9906087555. The cubic root of 644956339 is about 863.9927639104.

The spelling of 644956339 in words is "six hundred forty-four million, nine hundred fifty-six thousand, three hundred thirty-nine".