664560640 has 176 divisors, whose sum is σ = 1697863680. Its totient is φ = 249200640.

The previous prime is 664560619. The next prime is 664560641. The reversal of 664560640 is 46065466.

It is a self number, because there is not a number n which added to its sum of digits gives 664560640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664560641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8412121 + ... + 8412199.

Almost surely, 2^664560640 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 664560640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (848931840).

664560640 is an abundant number, since it is smaller than the sum of its proper divisors (1033303040).

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

664560640 is a wasteful number, since it uses less digits than its factorization.

664560640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 37.

The square root of 664560640 is about 25779.0736839011. The cubic root of 664560640 is about 872.6596024972.

The spelling of 664560640 in words is "six hundred sixty-four million, five hundred sixty thousand, six hundred forty".