664431768 has 384 divisors, whose sum is σ = 2528064000. Its totient is φ = 158941440.

The previous prime is 664431727. The next prime is 664431793. The reversal of 664431768 is 867134466.

It is a happy number.

664431768 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1513293 + ... + 1513731.

It is an arithmetic number, because the mean of its divisors is an integer number (6583500).

Almost surely, 2^664431768 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 664431768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1264032000).

664431768 is an abundant number, since it is smaller than the sum of its proper divisors (1863632232).

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

664431768 is a wasteful number, since it uses less digits than its factorization.

664431768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492 (or 475 counting only the distinct ones).

The product of its digits is 580608, while the sum is 45.

The square root of 664431768 is about 25776.5740159549. The cubic root of 664431768 is about 872.6031899584.

The spelling of 664431768 in words is "six hundred sixty-four million, four hundred thirty-one thousand, seven hundred sixty-eight".