664972 has 48 divisors (see below), whose sum is σ = 1548288. Its totient is φ = 241920.

The previous prime is 664967. The next prime is 664973. The reversal of 664972 is 279466.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a d-powerful number, because it can be written as 6 + 6² + 9⁶ + 4² + 7⁴ + 2¹⁷ .

It is not an unprimeable number, because it can be changed into a prime (664973) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5173 + ... + 5299.

It is an arithmetic number, because the mean of its divisors is an integer number (32256).

2⁶⁶⁴⁹⁷² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (774144).

664972 is an abundant number, since it is smaller than the sum of its proper divisors (883316).

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

664972 is a wasteful number, since it uses less digits than its factorization.

664972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 164 counting only the distinct ones).

The product of its digits is 18144, while the sum is 34.

The square root of 664972 is about 815.4581534328. The cubic root of 664972 is about 87.2839622794.

The spelling of 664972 in words is "six hundred sixty-four thousand, nine hundred seventy-two".