644626063 has 2 divisors, whose sum is σ = 644626064. Its totient is φ = 644626062.

The previous prime is 644626051. The next prime is 644626133. The reversal of 644626063 is 360626446.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644626063 is a prime.

It is a super-2 number, since 2×644626063² = 831085522197759938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644626163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322313031 + 322313032.

It is an arithmetic number, because the mean of its divisors is an integer number (322313032).

Almost surely, 2^644626063 is an apocalyptic number.

644626063 is a deficient number, since it is larger than the sum of its proper divisors (1).

644626063 is an equidigital number, since it uses as much as digits as its factorization.

644626063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 37.

The square root of 644626063 is about 25389.4872535859. The cubic root of 644626063 is about 863.8452579063.

The spelling of 644626063 in words is "six hundred forty-four million, six hundred twenty-six thousand, sixty-three".