664686646 has 8 divisors (see below), whose sum is σ = 1073724624. Its totient is φ = 306778440.

The previous prime is 664686623. The next prime is 664686703. The reversal of 664686646 is 646686466.

664686646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 664686593 and 664686602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12782410 + ... + 12782461.

It is an arithmetic number, because the mean of its divisors is an integer number (134215578).

Almost surely, 2^664686646 is an apocalyptic number.

664686646 is a deficient number, since it is larger than the sum of its proper divisors (409037978).

664686646 is a wasteful number, since it uses less digits than its factorization.

664686646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25564886.

The product of its digits is 5971968, while the sum is 52.

The square root of 664686646 is about 25781.5175270968. The cubic root of 664686646 is about 872.7147534196.

The spelling of 664686646 in words is "six hundred sixty-four million, six hundred eighty-six thousand, six hundred forty-six".