668172 has 12 divisors (see below), whose sum is σ = 1559096. Its totient is φ = 222720.

The previous prime is 668159. The next prime is 668179. The reversal of 668172 is 271866.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (668179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27829 + ... + 27852.

2⁶⁶⁸¹⁷² is an apocalyptic number.

It is an amenable number.

668172 is an abundant number, since it is smaller than the sum of its proper divisors (890924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

668172 is a wasteful number, since it uses less digits than its factorization.

668172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55688 (or 55686 counting only the distinct ones).

The product of its digits is 4032, while the sum is 30.

The square root of 668172 is about 817.4178857843. The cubic root of 668172 is about 87.4237485363.

The spelling of 668172 in words is "six hundred sixty-eight thousand, one hundred seventy-two".