664917760 has 144 divisors (see below), whose sum is σ = 1771902720. Its totient is φ = 237404160.

The previous prime is 664917733. The next prime is 664917797. The reversal of 664917760 is 67719466.

It is a self number, because there is not a number n which added to its sum of digits gives 664917760.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 515196 + ... + 516484.

It is an arithmetic number, because the mean of its divisors is an integer number (12304880).

Almost surely, 2^664917760 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 664917760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885951360).

664917760 is an abundant number, since it is smaller than the sum of its proper divisors (1106984960).

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

664917760 is a wasteful number, since it uses less digits than its factorization.

664917760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354 (or 1340 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 46.

The square root of 664917760 is about 25785.9993019468. Note that the first 3 decimals coincide. The cubic root of 664917760 is about 872.8158904121.

The spelling of 664917760 in words is "six hundred sixty-four million, nine hundred seventeen thousand, seven hundred sixty".