644374942213 has 2 divisors, whose sum is σ = 644374942214. Its totient is φ = 644374942212.

The previous prime is 644374942199. The next prime is 644374942249. The reversal of 644374942213 is 312249473446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 559074730369 + 85300211844 = 747713^2 + 292062^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644374942213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644374982213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322187471106 + 322187471107.

It is an arithmetic number, because the mean of its divisors is an integer number (322187471107).

Almost surely, 2^644374942213 is an apocalyptic number.

It is an amenable number.

644374942213 is a deficient number, since it is larger than the sum of its proper divisors (1).

644374942213 is an equidigital number, since it uses as much as digits as its factorization.

644374942213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3483648, while the sum is 49.

The spelling of 644374942213 in words is "six hundred forty-four billion, three hundred seventy-four million, nine hundred forty-two thousand, two hundred thirteen".