644607 has 12 divisors (see below), whose sum is σ = 945880. Its totient is φ = 422928.

The previous prime is 644599. The next prime is 644617. The reversal of 644607 is 706446.

It is not a de Polignac number, because 644607 - 2³ = 644599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644607.

It is not an unprimeable number, because it can be changed into a prime (644617) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69 + ... + 1137.

2⁶⁴⁴⁶⁰⁷ is an apocalyptic number.

644607 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

644607 is a deficient number, since it is larger than the sum of its proper divisors (301273).

644607 is a wasteful number, since it uses less digits than its factorization.

644607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142 (or 1139 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 644607 is about 802.8742118165. The cubic root of 644607 is about 86.3836742559.

The spelling of 644607 in words is "six hundred forty-four thousand, six hundred seven".