666216706660 has 12 divisors (see below), whose sum is σ = 1399055084028. Its totient is φ = 266486682656.

The previous prime is 666216706559. The next prime is 666216706691. The reversal of 666216706660 is 66607612666.

It can be written as a sum of positive squares in 2 ways, for example, as 179579317824 + 486637388836 = 423768^2 + 697594^2 .

It is a junction number, because it is equal to n+sod(n) for n = 666216706598 and 666216706607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16655417647 + ... + 16655417686.

It is an arithmetic number, because the mean of its divisors is an integer number (116587923669).

Almost surely, 2^666216706660 is an apocalyptic number.

It is an amenable number.

666216706660 is an abundant number, since it is smaller than the sum of its proper divisors (732838377368).

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

666216706660 is a wasteful number, since it uses less digits than its factorization.

666216706660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33310835342 (or 33310835340 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 52.

The spelling of 666216706660 in words is "six hundred sixty-six billion, two hundred sixteen million, seven hundred six thousand, six hundred sixty".