664355520 has 420 divisors, whose sum is σ = 2529285264. Its totient is φ = 165473280.

The previous prime is 664355507. The next prime is 664355521. The reversal of 664355520 is 25553466.

It is a happy number.

664355520 is a `hidden beast` number, since 6 + 643 + 5 + 5 + 5 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (664355521) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 9357085 + ... + 9357155.

Almost surely, 2^664355520 is an apocalyptic number.

664355520 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 664355520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1264642632).

664355520 is an abundant number, since it is smaller than the sum of its proper divisors (1864929744).

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

664355520 is a wasteful number, since it uses less digits than its factorization.

664355520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 36.

The square root of 664355520 is about 25775.0949561781. The cubic root of 664355520 is about 872.5698096594.

The spelling of 664355520 in words is "six hundred sixty-four million, three hundred fifty-five thousand, five hundred twenty".