644883929 has 2 divisors, whose sum is σ = 644883930. Its totient is φ = 644883928.

The previous prime is 644883907. The next prime is 644883949. The reversal of 644883929 is 929388446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 397922704 + 246961225 = 19948^2 + 15715^2 .

It is a cyclic number.

It is not a de Polignac number, because 644883929 - 2²⁸ = 376448473 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644883949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322441964 + 322441965.

It is an arithmetic number, because the mean of its divisors is an integer number (322441965).

Almost surely, 2^644883929 is an apocalyptic number.

It is an amenable number.

644883929 is a deficient number, since it is larger than the sum of its proper divisors (1).

644883929 is an equidigital number, since it uses as much as digits as its factorization.

644883929 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2985984, while the sum is 53.

The square root of 644883929 is about 25394.5649500046. The cubic root of 644883929 is about 863.9604288754.

It can be divided in two parts, 64488 and 3929, that multiplied together give a palindrome (253373352).

The spelling of 644883929 in words is "six hundred forty-four million, eight hundred eighty-three thousand, nine hundred twenty-nine".