644374942163 has 2 divisors, whose sum is σ = 644374942164. Its totient is φ = 644374942162.

The previous prime is 644374942129. The next prime is 644374942193. The reversal of 644374942163 is 361249473446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644374942163 - 2¹⁶ = 644374876627 is a prime.

It is not a weakly prime, because it can be changed into another prime (644374942193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322187471081 + 322187471082.

It is an arithmetic number, because the mean of its divisors is an integer number (322187471082).

Almost surely, 2^644374942163 is an apocalyptic number.

644374942163 is a deficient number, since it is larger than the sum of its proper divisors (1).

644374942163 is an equidigital number, since it uses as much as digits as its factorization.

644374942163 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 53.

The spelling of 644374942163 in words is "six hundred forty-four billion, three hundred seventy-four million, nine hundred forty-two thousand, one hundred sixty-three".