644201933 has 2 divisors, whose sum is σ = 644201934. Its totient is φ = 644201932.

The previous prime is 644201923. The next prime is 644201939. The reversal of 644201933 is 339102446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 391169284 + 253032649 = 19778^2 + 15907^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644201933 is a prime.

It is a super-2 number, since 2×644201933² = 829992260961872978, which contains 22 as substring.

It is equal to p_33507536 and since 644201933 and 33507536 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644201933.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644201939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322100966 + 322100967.

It is an arithmetic number, because the mean of its divisors is an integer number (322100967).

Almost surely, 2^644201933 is an apocalyptic number.

It is an amenable number.

644201933 is a deficient number, since it is larger than the sum of its proper divisors (1).

644201933 is an equidigital number, since it uses as much as digits as its factorization.

644201933 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 644201933 is about 25381.1334065286. The cubic root of 644201933 is about 863.6557614456.

The spelling of 644201933 in words is "six hundred forty-four million, two hundred one thousand, nine hundred thirty-three".