644692199 has 2 divisors, whose sum is σ = 644692200. Its totient is φ = 644692198.

The previous prime is 644692171. The next prime is 644692261. The reversal of 644692199 is 991296446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644692199 - 2²⁸ = 376256743 is a 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 (644692109) 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, 322346099 + 322346100.

It is an arithmetic number, because the mean of its divisors is an integer number (322346100).

Almost surely, 2^644692199 is an apocalyptic number.

644692199 is a deficient number, since it is larger than the sum of its proper divisors (1).

644692199 is an equidigital number, since it uses as much as digits as its factorization.

644692199 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 50.

The square root of 644692199 is about 25390.7896490046. The cubic root of 644692199 is about 863.8747992272.

The spelling of 644692199 in words is "six hundred forty-four million, six hundred ninety-two thousand, one hundred ninety-nine".