644464612 has 24 divisors (see below), whose sum is σ = 1231034112. Its totient is φ = 292773600.

The previous prime is 644464603. The next prime is 644464621. The reversal of 644464612 is 216464446.

It is an interprime number because it is at equal distance from previous prime (644464603) and next prime (644464621).

It is a super-2 number, since 2×644464612² = 830669272240621088, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111178 + ... + 116830.

It is an arithmetic number, because the mean of its divisors is an integer number (51293088).

Almost surely, 2^644464612 is an apocalyptic number.

644464612 is the 20728-th pentagonal number.

It is an amenable number.

644464612 is a deficient number, since it is larger than the sum of its proper divisors (586569500).

644464612 is a wasteful number, since it uses less digits than its factorization.

644464612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8259 (or 8257 counting only the distinct ones).

The product of its digits is 110592, while the sum is 37.

The square root of 644464612 is about 25386.3075692390. The cubic root of 644464612 is about 863.7731332364.

The spelling of 644464612 in words is "six hundred forty-four million, four hundred sixty-four thousand, six hundred twelve".