644164967 has 2 divisors, whose sum is σ = 644164968. Its totient is φ = 644164966.

The previous prime is 644164957. The next prime is 644165017. The reversal of 644164967 is 769461446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644164967 - 2⁴ = 644164951 is a prime.

It is a super-2 number, since 2×644164967² = 829897009420222178, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644164957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322082483 + 322082484.

It is an arithmetic number, because the mean of its divisors is an integer number (322082484).

Almost surely, 2^644164967 is an apocalyptic number.

644164967 is a deficient number, since it is larger than the sum of its proper divisors (1).

644164967 is an equidigital number, since it uses as much as digits as its factorization.

644164967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 47.

The square root of 644164967 is about 25380.4051780109. The cubic root of 644164967 is about 863.6392415171.

The spelling of 644164967 in words is "six hundred forty-four million, one hundred sixty-four thousand, nine hundred sixty-seven".