665172 has 30 divisors (see below), whose sum is σ = 1739738. Its totient is φ = 221616.

The previous prime is 665153. The next prime is 665177. The reversal of 665172 is 271566.

665172 is a `hidden beast` number, since 6 + 651 + 7 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 571536 + 93636 = 756^2 + 306^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665177) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 703 + ... + 1350.

2⁶⁶⁵¹⁷² is an apocalyptic number.

It is an amenable number.

665172 is an abundant number, since it is smaller than the sum of its proper divisors (1074566).

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

665172 is a wasteful number, since it uses less digits than its factorization.

665172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2069 (or 2058 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 665172 is about 815.5807746631. The cubic root of 665172 is about 87.2927120426.

The spelling of 665172 in words is "six hundred sixty-five thousand, one hundred seventy-two".