664072640 has 112 divisors (see below), whose sum is σ = 1971592704. Its totient is φ = 206976000.

The previous prime is 664072579. The next prime is 664072687. The reversal of 664072640 is 46270466.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 664072640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11165 + ... + 38115.

Almost surely, 2^664072640 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 664072640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (985796352).

664072640 is an abundant number, since it is smaller than the sum of its proper divisors (1307520064).

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

664072640 is a wasteful number, since it uses less digits than its factorization.

664072640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26986 (or 26976 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 664072640 is about 25769.6069042584. The cubic root of 664072640 is about 872.4459464656.

The spelling of 664072640 in words is "six hundred sixty-four million, seventy-two thousand, six hundred forty".