66723664 has 40 divisors (see below), whose sum is σ = 152847360. Its totient is φ = 27608448.

The previous prime is 66723583. The next prime is 66723677. The reversal of 66723664 is 46632766.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7024 + ... + 13519.

It is an arithmetic number, because the mean of its divisors is an integer number (3821184).

Almost surely, 2^66723664 is an apocalyptic number.

It is an amenable number.

66723664 is an abundant number, since it is smaller than the sum of its proper divisors (86123696).

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

66723664 is a wasteful number, since it uses less digits than its factorization.

66723664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20587 (or 20581 counting only the distinct ones).

The product of its digits is 217728, while the sum is 40.

The square root of 66723664 is about 8168.4554231507. The cubic root of 66723664 is about 405.5956565533.

The spelling of 66723664 in words is "sixty-six million, seven hundred twenty-three thousand, six hundred sixty-four".