644677 has 8 divisors (see below), whose sum is σ = 711360. Its totient is φ = 579360.

The previous prime is 644671. The next prime is 644687. The reversal of 644677 is 776446.

644677 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 644677 - 2³ = 644669 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 644677.

It is not an unprimeable number, because it can be changed into a prime (644671) 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, 849 + ... + 1417.

It is an arithmetic number, because the mean of its divisors is an integer number (88920).

2⁶⁴⁴⁶⁷⁷ is an apocalyptic number.

It is an amenable number.

644677 is a deficient number, since it is larger than the sum of its proper divisors (66683).

644677 is a wasteful number, since it uses less digits than its factorization.

644677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 683.

The product of its digits is 28224, while the sum is 34.

The square root of 644677 is about 802.9178040123. The cubic root of 644677 is about 86.3868010387.

Subtracting 644677 from its reverse (776446), we obtain a square (131769 = 363²).

The spelling of 644677 in words is "six hundred forty-four thousand, six hundred seventy-seven".