644179799 has 2 divisors, whose sum is σ = 644179800. Its totient is φ = 644179798.

The previous prime is 644179777. The next prime is 644179829. The reversal of 644179799 is 997971446.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644179799 is a prime.

It is a super-2 number, since 2×644179799² = 829935226879360802, which contains 22 as substring.

It is a Sophie Germain 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 (644179769) 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, 322089899 + 322089900.

It is an arithmetic number, because the mean of its divisors is an integer number (322089900).

Almost surely, 2^644179799 is an apocalyptic number.

644179799 is a deficient number, since it is larger than the sum of its proper divisors (1).

644179799 is an equidigital number, since it uses as much as digits as its factorization.

644179799 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3429216, while the sum is 56.

The square root of 644179799 is about 25380.6973702458. The cubic root of 644179799 is about 863.6458699429.

The spelling of 644179799 in words is "six hundred forty-four million, one hundred seventy-nine thousand, seven hundred ninety-nine".