644064007 has 2 divisors, whose sum is σ = 644064008. Its totient is φ = 644064006.

The previous prime is 644063951. The next prime is 644064037. The reversal of 644064007 is 700460446.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644064007 is a prime.

It is a super-2 number, since 2×644064007² = 829636890225792098, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644064007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644064037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322032003 + 322032004.

It is an arithmetic number, because the mean of its divisors is an integer number (322032004).

Almost surely, 2^644064007 is an apocalyptic number.

644064007 is a deficient number, since it is larger than the sum of its proper divisors (1).

644064007 is an equidigital number, since it uses as much as digits as its factorization.

644064007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 31.

The square root of 644064007 is about 25378.4161641344. The cubic root of 644064007 is about 863.5941197559.

The spelling of 644064007 in words is "six hundred forty-four million, sixty-four thousand, seven".