66764720 has 40 divisors (see below), whose sum is σ = 169341840. Its totient is φ = 24277760.

The previous prime is 66764713. The next prime is 66764743. The reversal of 66764720 is 2746766.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

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, 37055 + ... + 38814.

It is an arithmetic number, because the mean of its divisors is an integer number (4233546).

Almost surely, 2^66764720 is an apocalyptic number.

It is an amenable number.

66764720 is an abundant number, since it is smaller than the sum of its proper divisors (102577120).

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

66764720 is a wasteful number, since it uses less digits than its factorization.

66764720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75893 (or 75887 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 38.

The square root of 66764720 is about 8170.9681188951. The cubic root of 66764720 is about 405.6788290492.

The spelling of 66764720 in words is "sixty-six million, seven hundred sixty-four thousand, seven hundred twenty".