664662726 has 128 divisors (see below), whose sum is σ = 1862784000. Its totient is φ = 170968320.

The previous prime is 664662703. The next prime is 664662743. The reversal of 664662726 is 627266466.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 199825 + ... + 203123.

It is an arithmetic number, because the mean of its divisors is an integer number (14553000).

Almost surely, 2^664662726 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664662726, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (931392000).

664662726 is an abundant number, since it is smaller than the sum of its proper divisors (1198121274).

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

664662726 is a wasteful number, since it uses less digits than its factorization.

664662726 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3371 (or 3365 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 664662726 is about 25781.0536247067. The cubic root of 664662726 is about 872.7042845330.

The spelling of 664662726 in words is "six hundred sixty-four million, six hundred sixty-two thousand, seven hundred twenty-six".