664357680 has 240 divisors, whose sum is σ = 2662374240. Its totient is φ = 151828992.

The previous prime is 664357679. The next prime is 664357747. The reversal of 664357680 is 86753466.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×664357680² = 882742253949964800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 102702 + ... + 108978.

It is an arithmetic number, because the mean of its divisors is an integer number (11093226).

Almost surely, 2^664357680 is an apocalyptic number.

664357680 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 664357680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1331187120).

664357680 is an abundant number, since it is smaller than the sum of its proper divisors (1998016560).

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

664357680 is a wasteful number, since it uses less digits than its factorization.

664357680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6313 (or 6294 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 664357680 is about 25775.1368570566. The cubic root of 664357680 is about 872.5707553121.

The spelling of 664357680 in words is "six hundred sixty-four million, three hundred fifty-seven thousand, six hundred eighty".