666698880 has 64 divisors (see below), whose sum is σ = 2125108800. Its totient is φ = 177785856.

The previous prime is 666698873. The next prime is 666698881. The reversal of 666698880 is 88896666.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 666698880.

It is not an unprimeable number, because it can be changed into a prime (666698881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171700 + ... + 175539.

It is an arithmetic number, because the mean of its divisors is an integer number (33204825).

Almost surely, 2^666698880 is an apocalyptic number.

666698880 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666698880 is an abundant number, since it is smaller than the sum of its proper divisors (1458409920).

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

666698880 is a wasteful number, since it uses less digits than its factorization.

666698880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347261 (or 347249 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 57.

The square root of 666698880 is about 25820.5127756983. The cubic root of 666698880 is about 873.5945349790.

The spelling of 666698880 in words is "six hundred sixty-six million, six hundred ninety-eight thousand, eight hundred eighty".