644064367 has 8 divisors (see below), whose sum is σ = 669623472. Its totient is φ = 618974400.

The previous prime is 644064341. The next prime is 644064389. The reversal of 644064367 is 763460446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644064367 - 2¹⁵ = 644031599 is a prime.

It is a super-2 number, since 2×644064367² = 829637817678221378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644064307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114484 + ... + 119977.

It is an arithmetic number, because the mean of its divisors is an integer number (83702934).

Almost surely, 2^644064367 is an apocalyptic number.

644064367 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

644064367 is a deficient number, since it is larger than the sum of its proper divisors (25559105).

644064367 is a wasteful number, since it uses less digits than its factorization.

644064367 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234569.

The product of its (nonzero) digits is 290304, while the sum is 40.

The square root of 644064367 is about 25378.4232567746. The cubic root of 644064367 is about 863.5942806581.

It can be divided in two parts, 6440 and 64367, that added together give a palindrome (70807).

The spelling of 644064367 in words is "six hundred forty-four million, sixty-four thousand, three hundred sixty-seven".