66764916 has 72 divisors (see below), whose sum is σ = 180311040. Its totient is φ = 20756736.

The previous prime is 66764911. The next prime is 66764923. The reversal of 66764916 is 61946766.

It is a happy number.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

Its product of digits (326592) is a multiple of the sum of its prime divisors (1008).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66764911) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77295 + ... + 78153.

It is an arithmetic number, because the mean of its divisors is an integer number (2504320).

Almost surely, 2^66764916 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66764916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90155520).

66764916 is an abundant number, since it is smaller than the sum of its proper divisors (113546124).

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

66764916 is a wasteful number, since it uses less digits than its factorization.

66764916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1013 (or 1008 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 66764916 is about 8170.9801125691. The cubic root of 66764916 is about 405.6792260302.

The spelling of 66764916 in words is "sixty-six million, seven hundred sixty-four thousand, nine hundred sixteen".