668635 has 8 divisors (see below), whose sum is σ = 875376. Its totient is φ = 486240.

The previous prime is 668623. The next prime is 668671. The reversal of 668635 is 536866.

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

It is not a de Polignac number, because 668635 - 2¹⁵ = 635867 is a prime.

It is an Ulam number.

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 668635.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6024 + ... + 6133.

It is an arithmetic number, because the mean of its divisors is an integer number (109422).

2⁶⁶⁸⁶³⁵ is an apocalyptic number.

668635 is a deficient number, since it is larger than the sum of its proper divisors (206741).

668635 is a wasteful number, since it uses less digits than its factorization.

668635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12173.

The product of its digits is 25920, while the sum is 34.

The square root of 668635 is about 817.7010456151. The cubic root of 668635 is about 87.4439368759.

Subtracting from 668635 its reverse (536866), we obtain a square (131769 = 363²).

The spelling of 668635 in words is "six hundred sixty-eight thousand, six hundred thirty-five".