644629718933 has 2 divisors, whose sum is σ = 644629718934. Its totient is φ = 644629718932.

The previous prime is 644629718881. The next prime is 644629718987. The reversal of 644629718933 is 339817926446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 361342849924 + 283286869009 = 601118^2 + 532247^2 .

It is a cyclic number.

It is not a de Polignac number, because 644629718933 - 2⁶ = 644629718869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644629718833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322314859466 + 322314859467.

It is an arithmetic number, because the mean of its divisors is an integer number (322314859467).

Almost surely, 2^644629718933 is an apocalyptic number.

It is an amenable number.

644629718933 is a deficient number, since it is larger than the sum of its proper divisors (1).

644629718933 is an equidigital number, since it uses as much as digits as its factorization.

644629718933 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47029248, while the sum is 62.

The spelling of 644629718933 in words is "six hundred forty-four billion, six hundred twenty-nine million, seven hundred eighteen thousand, nine hundred thirty-three".