664759872 has 210 divisors, whose sum is σ = 2293155942. Its totient is φ = 189858816.

The previous prime is 664759853. The next prime is 664759873. The reversal of 664759872 is 278957466.

664759872 is a `hidden beast` number, since 6 + 6 + 47 + 598 + 7 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 660695616 + 4064256 = 25704^2 + 2016^2 .

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (664759873) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 252708 + ... + 255324.

Almost surely, 2^664759872 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 664759872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1146577971).

664759872 is an abundant number, since it is smaller than the sum of its proper divisors (1628396070).

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

664759872 is a wasteful number, since it uses less digits than its factorization.

664759872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2655 (or 2629 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 54.

The square root of 664759872 is about 25782.9376138562. The cubic root of 664759872 is about 872.7468001312.

The spelling of 664759872 in words is "six hundred sixty-four million, seven hundred fifty-nine thousand, eight hundred seventy-two".