664727724 has 18 divisors (see below), whose sum is σ = 1680284060. Its totient is φ = 221575896.

The previous prime is 664727719. The next prime is 664727729. The reversal of 664727724 is 427727466.

It is an interprime number because it is at equal distance from previous prime (664727719) and next prime (664727729).

It is a tau number, because it is divible by the number of its divisors (18).

It is a self number, because there is not a number n which added to its sum of digits gives 664727724.

It is not an unprimeable number, because it can be changed into a prime (664727729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9232294 + ... + 9232365.

Almost surely, 2^664727724 is an apocalyptic number.

It is an amenable number.

664727724 is an abundant number, since it is smaller than the sum of its proper divisors (1015556336).

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

664727724 is a wasteful number, since it uses less digits than its factorization.

664727724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18464669 (or 18464664 counting only the distinct ones).

The product of its digits is 790272, while the sum is 45.

The square root of 664727724 is about 25782.3141707644. The cubic root of 664727724 is about 872.7327311330.

The spelling of 664727724 in words is "six hundred sixty-four million, seven hundred twenty-seven thousand, seven hundred twenty-four".