664993720664 has 256 divisors, whose sum is σ = 1633629634560. Its totient is φ = 246722112000.

The previous prime is 664993720663. The next prime is 664993720669. The reversal of 664993720664 is 466027399466.

It is a Harshad number since it is a multiple of its sum of digits (62).

It is a junction number, because it is equal to n+sod(n) for n = 664993720597 and 664993720606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664993720663) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 127122929 + ... + 127128159.

It is an arithmetic number, because the mean of its divisors is an integer number (6381365760).

Almost surely, 2^664993720664 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 664993720664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (816814817280).

664993720664 is an abundant number, since it is smaller than the sum of its proper divisors (968635913896).

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

664993720664 is a wasteful number, since it uses less digits than its factorization.

664993720664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5462 (or 5458 counting only the distinct ones).

The product of its (nonzero) digits is 70543872, while the sum is 62.

The spelling of 664993720664 in words is "six hundred sixty-four billion, nine hundred ninety-three million, seven hundred twenty thousand, six hundred sixty-four".