666665760 has 48 divisors (see below), whose sum is σ = 2099998656. Its totient is φ = 177777408.

The previous prime is 666665759. The next prime is 666665801. The reversal of 666665760 is 67566666.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 693964 + ... + 694923.

It is an arithmetic number, because the mean of its divisors is an integer number (43749972).

Almost surely, 2^666665760 is an apocalyptic number.

666665760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666665760 is an abundant number, since it is smaller than the sum of its proper divisors (1433332896).

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

666665760 is a wasteful number, since it uses less digits than its factorization.

666665760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1388905 (or 1388897 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 48.

The square root of 666665760 is about 25819.8714171856. The cubic root of 666665760 is about 873.5800687130.

The spelling of 666665760 in words is "six hundred sixty-six million, six hundred sixty-five thousand, seven hundred sixty".