666666660 has 192 divisors, whose sum is σ = 2099913984. Its totient is φ = 156672000.

The previous prime is 666666653. The next prime is 666666667. The reversal of 666666660 is 66666666.

666666660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (666666653) and next prime (666666667).

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666666667) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4866112 + ... + 4866248.

It is an arithmetic number, because the mean of its divisors is an integer number (10937052).

Almost surely, 2^666666660 is an apocalyptic number.

666666660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666666660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1049956992).

666666660 is an abundant number, since it is smaller than the sum of its proper divisors (1433247324).

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

666666660 is a wasteful number, since it uses less digits than its factorization.

666666660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334 (or 332 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 48.

The square root of 666666660 is about 25819.8888456167. Note that the first 4 decimals coincide. The cubic root of 666666660 is about 873.5804618244.

It can be divided in two parts, 6666666 and 60, that added together give a triangular number (6666726 = T₃₆₅₁).

The spelling of 666666660 in words is "six hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty".