644460666064373 has 2 divisors, whose sum is σ = 644460666064374. Its totient is φ = 644460666064372.

The previous prime is 644460666064343. The next prime is 644460666064463. The reversal of 644460666064373 is 373460666064446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 476573655541489 + 167887010522884 = 21830567^2 + 12957122^2 .

It is a cyclic number.

It is not a de Polignac number, because 644460666064373 - 2⁶ = 644460666064309 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644460666064343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322230333032186 + 322230333032187.

It is an arithmetic number, because the mean of its divisors is an integer number (322230333032187).

Almost surely, 2^{644460666064373} is an apocalyptic number.

It is an amenable number.

644460666064373 is a deficient number, since it is larger than the sum of its proper divisors (1).

644460666064373 is an equidigital number, since it uses as much as digits as its factorization.

644460666064373 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 752467968, while the sum is 65.

The spelling of 644460666064373 in words is "six hundred forty-four trillion, four hundred sixty billion, six hundred sixty-six million, sixty-four thousand, three hundred seventy-three".