668772 has 36 divisors (see below), whose sum is σ = 1821820. Its totient is φ = 205632.

The previous prime is 668761. The next prime is 668791. The reversal of 668772 is 277866.

It can be written as a sum of positive squares in 2 ways, for example, as 69696 + 599076 = 264^2 + 774^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

668772 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 247 + ... + 1182.

2⁶⁶⁸⁷⁷² is an apocalyptic number.

It is an amenable number.

668772 is an abundant number, since it is smaller than the sum of its proper divisors (1153048).

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

668772 is a wasteful number, since it uses less digits than its factorization.

668772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452 (or 1447 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 668772 is about 817.7848127717. The cubic root of 668772 is about 87.4499087446.

The spelling of 668772 in words is "six hundred sixty-eight thousand, seven hundred seventy-two".