664642 has 8 divisors (see below), whose sum is σ = 1087632. Its totient is φ = 302100.

The previous prime is 664633. The next prime is 664661. The reversal of 664642 is 246466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 664642.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15084 + ... + 15127.

It is an arithmetic number, because the mean of its divisors is an integer number (135954).

2⁶⁶⁴⁶⁴² is an apocalyptic number.

664642 is a deficient number, since it is larger than the sum of its proper divisors (422990).

664642 is a wasteful number, since it uses less digits than its factorization.

664642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30224.

The product of its digits is 6912, while the sum is 28.

The square root of 664642 is about 815.2557880813. The cubic root of 664642 is about 87.2695213337.

It can be divided in two parts, 66464 and 2, that added together give a palindrome (66466).

The spelling of 664642 in words is "six hundred sixty-four thousand, six hundred forty-two".