666939180961 has 16 divisors (see below), whose sum is σ = 679250613888. Its totient is φ = 654710560000.

The previous prime is 666939180883. The next prime is 666939180979. The reversal of 666939180961 is 169081939666.

It is a cyclic number.

It is not a de Polignac number, because 666939180961 - 2⁷ = 666939180833 is a prime.

It is a super-2 number, since 2×666939180961² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666939180893 and 666939180902.

It is not an unprimeable number, because it can be changed into a prime (666939180161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97602201 + ... + 97609033.

It is an arithmetic number, because the mean of its divisors is an integer number (42453163368).

Almost surely, 2^666939180961 is an apocalyptic number.

It is an amenable number.

666939180961 is a deficient number, since it is larger than the sum of its proper divisors (12311432927).

666939180961 is a wasteful number, since it uses less digits than its factorization.

666939180961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12632.

The product of its (nonzero) digits is 22674816, while the sum is 64.

The spelling of 666939180961 in words is "six hundred sixty-six billion, nine hundred thirty-nine million, one hundred eighty thousand, nine hundred sixty-one".