665723124 has 90 divisors (see below), whose sum is σ = 1913039282. Its totient is φ = 201722400.

The previous prime is 665723117. The next prime is 665723167. The reversal of 665723124 is 421327566.

665723124 is a `hidden beast` number, since 66 + 572 + 3 + 1 + 24 = 666.

665723124 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 662547600 + 3175524 = 25740^2 + 1782^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 30714 + ... + 47694.

Almost surely, 2^665723124 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 665723124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (956519641).

665723124 is an abundant number, since it is smaller than the sum of its proper divisors (1247316158).

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

665723124 is a wasteful number, since it uses less digits than its factorization.

665723124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17019 (or 16997 counting only the distinct ones).

The product of its digits is 60480, while the sum is 36.

The square root of 665723124 is about 25801.6108799431. The cubic root of 665723124 is about 873.1681399314.

It can be divided in two parts, 66572 and 3124, that added together give a palindrome (69696).

The spelling of 665723124 in words is "six hundred sixty-five million, seven hundred twenty-three thousand, one hundred twenty-four".