664631 has 16 divisors (see below), whose sum is σ = 787968. Its totient is φ = 554400.

The previous prime is 664621. The next prime is 664633. The reversal of 664631 is 136466.

It is not a de Polignac number, because 664631 - 2¹⁸ = 402487 is a prime.

It is a super-2 number, since 2×664631² = 883468732322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9326 + ... + 9396.

It is an arithmetic number, because the mean of its divisors is an integer number (49248).

2⁶⁶⁴⁶³¹ is an apocalyptic number.

664631 is a deficient number, since it is larger than the sum of its proper divisors (123337).

664631 is a wasteful number, since it uses less digits than its factorization.

664631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142.

The product of its digits is 2592, while the sum is 26.

The square root of 664631 is about 815.2490417044. The cubic root of 664631 is about 87.2690398866.

The spelling of 664631 in words is "six hundred sixty-four thousand, six hundred thirty-one".