665724 has 24 divisors (see below), whose sum is σ = 1607760. Its totient is φ = 214144.

The previous prime is 665723. The next prime is 665747. The reversal of 665724 is 427566.

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 a junction number, because it is equal to n+sod(n) for n = 665691 and 665700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 609 + ... + 1304.

It is an arithmetic number, because the mean of its divisors is an integer number (66990).

2⁶⁶⁵⁷²⁴ is an apocalyptic number.

It is an amenable number.

665724 is an abundant number, since it is smaller than the sum of its proper divisors (942036).

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

665724 is a wasteful number, since it uses less digits than its factorization.

665724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1949 (or 1947 counting only the distinct ones).

The product of its digits is 10080, while the sum is 30.

The square root of 665724 is about 815.9191136381. The cubic root of 665724 is about 87.3168522921.

The spelling of 665724 in words is "six hundred sixty-five thousand, seven hundred twenty-four".