644643107 has 2 divisors, whose sum is σ = 644643108. Its totient is φ = 644643106.

The previous prime is 644643053. The next prime is 644643121. The reversal of 644643107 is 701346446.

644643107 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644643107 - 2¹⁸ = 644380963 is a prime.

It is a super-2 number, since 2×644643107² = 831129470805226898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (644643607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322321553 + 322321554.

It is an arithmetic number, because the mean of its divisors is an integer number (322321554).

Almost surely, 2^644643107 is an apocalyptic number.

644643107 is a deficient number, since it is larger than the sum of its proper divisors (1).

644643107 is an equidigital number, since it uses as much as digits as its factorization.

644643107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 644643107 is about 25389.8229021000. The cubic root of 644643107 is about 863.8528712342.

The spelling of 644643107 in words is "six hundred forty-four million, six hundred forty-three thousand, one hundred seven".