666764880 has 80 divisors (see below), whose sum is σ = 2115072960. Its totient is φ = 173666304.

The previous prime is 666764863. The next prime is 666764887. The reversal of 666764880 is 88467666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666764887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21985 + ... + 42624.

It is an arithmetic number, because the mean of its divisors is an integer number (26438412).

Almost surely, 2^666764880 is an apocalyptic number.

666764880 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666764880 is an abundant number, since it is smaller than the sum of its proper divisors (1448308080).

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

666764880 is a wasteful number, since it uses less digits than its factorization.

666764880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64668 (or 64662 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 51.

The square root of 666764880 is about 25821.7907976964. The cubic root of 666764880 is about 873.6233612546.

The spelling of 666764880 in words is "six hundred sixty-six million, seven hundred sixty-four thousand, eight hundred eighty".