644479 has 8 divisors (see below), whose sum is σ = 720720. Its totient is φ = 571200.

The previous prime is 644447. The next prime is 644489. The reversal of 644479 is 974446.

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 644479 - 2⁵ = 644447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644489) 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, 264 + ... + 1165.

It is an arithmetic number, because the mean of its divisors is an integer number (90090).

2⁶⁴⁴⁴⁷⁹ is an apocalyptic number.

644479 is a deficient number, since it is larger than the sum of its proper divisors (76241).

644479 is a wasteful number, since it uses less digits than its factorization.

644479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481.

The product of its digits is 24192, while the sum is 34.

The square root of 644479 is about 802.7944942512. The cubic root of 644479 is about 86.3779561247.

The spelling of 644479 in words is "six hundred forty-four thousand, four hundred seventy-nine".