666405660 has 48 divisors (see below), whose sum is σ = 1868378400. Its totient is φ = 177475584.

The previous prime is 666405653. The next prime is 666405671. The reversal of 666405660 is 66504666.

666405660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41676 + ... + 55404.

It is an arithmetic number, because the mean of its divisors is an integer number (38924550).

Almost surely, 2^666405660 is an apocalyptic number.

666405660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666405660 is an abundant number, since it is smaller than the sum of its proper divisors (1201972740).

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

666405660 is a wasteful number, since it uses less digits than its factorization.

666405660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14550 (or 14548 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 39.

The square root of 666405660 is about 25814.8341075437. The cubic root of 666405660 is about 873.4664446924.

The spelling of 666405660 in words is "six hundred sixty-six million, four hundred five thousand, six hundred sixty".