644024131 has 2 divisors, whose sum is σ = 644024132. Its totient is φ = 644024130.

The previous prime is 644024111. The next prime is 644024137. The reversal of 644024131 is 131420446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644024131 - 2⁵ = 644024099 is a prime.

It is a super-2 number, since 2×644024131² = 829534162620610322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644024096 and 644024105.

It is not a weakly prime, because it can be changed into another prime (644024137) 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, 322012065 + 322012066.

It is an arithmetic number, because the mean of its divisors is an integer number (322012066).

Almost surely, 2^644024131 is an apocalyptic number.

644024131 is a deficient number, since it is larger than the sum of its proper divisors (1).

644024131 is an equidigital number, since it uses as much as digits as its factorization.

644024131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 644024131 is about 25377.6305237506. The cubic root of 644024131 is about 863.5762967914.

Adding to 644024131 its reverse (131420446), we get a palindrome (775444577).

The spelling of 644024131 in words is "six hundred forty-four million, twenty-four thousand, one hundred thirty-one".