668872 has 8 divisors (see below), whose sum is σ = 1254150. Its totient is φ = 334432.

The previous prime is 668869. The next prime is 668873. The reversal of 668872 is 278866.

It can be written as a sum of positive squares in only one way, i.e., 617796 + 51076 = 786^2 + 226^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (668873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41797 + ... + 41812.

2⁶⁶⁸⁸⁷² is an apocalyptic number.

It is an amenable number.

668872 is a deficient number, since it is larger than the sum of its proper divisors (585278).

668872 is a wasteful number, since it uses less digits than its factorization.

668872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83615 (or 83611 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 668872 is about 817.8459512647. The cubic root of 668872 is about 87.4542672580.

It can be divided in two parts, 668 and 872, that added together give a triangular number (1540 = T₅₅).

The spelling of 668872 in words is "six hundred sixty-eight thousand, eight hundred seventy-two".