664831 has 4 divisors (see below), whose sum is σ = 666472. Its totient is φ = 663192.

The previous prime is 664799. The next prime is 664843. The reversal of 664831 is 138466.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 138466 = 2 ⋅69233.

It is a cyclic number.

It is not a de Polignac number, because 664831 - 2⁵ = 664799 is a prime.

It is a super-2 number, since 2×664831² = 884000517122, which contains 22 as substring.

It is a Duffinian number.

664831 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 664831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 280 + ... + 1186.

It is an arithmetic number, because the mean of its divisors is an integer number (166618).

2⁶⁶⁴⁸³¹ is an apocalyptic number.

664831 is a deficient number, since it is larger than the sum of its proper divisors (1641).

664831 is an equidigital number, since it uses as much as digits as its factorization.

664831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1640.

The product of its digits is 3456, while the sum is 28.

The square root of 664831 is about 815.3716943824. The cubic root of 664831 is about 87.2777926419.

The spelling of 664831 in words is "six hundred sixty-four thousand, eight hundred thirty-one".