64666720 has 24 divisors (see below), whose sum is σ = 152775504. Its totient is φ = 25866624.

The previous prime is 64666681. The next prime is 64666727. The reversal of 64666720 is 2766646.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 64666720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64666727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201924 + ... + 202243.

It is an arithmetic number, because the mean of its divisors is an integer number (6365646).

Almost surely, 2^64666720 is an apocalyptic number.

It is an amenable number.

64666720 is an abundant number, since it is smaller than the sum of its proper divisors (88108784).

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

64666720 is a wasteful number, since it uses less digits than its factorization.

64666720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404182 (or 404174 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 37.

The square root of 64666720 is about 8041.5620373159. The cubic root of 64666720 is about 401.3842044200.

The spelling of 64666720 in words is "sixty-four million, six hundred sixty-six thousand, seven hundred twenty".