660388320 has 144 divisors (see below), whose sum is σ = 2372282640. Its totient is φ = 166828032.

The previous prime is 660388297. The next prime is 660388331. The reversal of 660388320 is 23883066.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×660388320² = 872225466384844800, which contains 22 as substring.

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 23 ways as a sum of consecutive naturals, for example, 15292 + ... + 39428.

It is an arithmetic number, because the mean of its divisors is an integer number (16474185).

Almost surely, 2^660388320 is an apocalyptic number.

660388320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 660388320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1186141320).

660388320 is an abundant number, since it is smaller than the sum of its proper divisors (1711894320).

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

660388320 is a wasteful number, since it uses less digits than its factorization.

660388320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24177 (or 24166 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 660388320 is about 25698.0217137429. The cubic root of 660388320 is about 870.8294902928.

The spelling of 660388320 in words is "six hundred sixty million, three hundred eighty-eight thousand, three hundred twenty".