666638836666 has 8 divisors (see below), whose sum is σ = 1090863550944. Its totient is φ = 303017653020.

The previous prime is 666638836663. The next prime is 666638836729.

666638836666 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 666638836595 and 666638836604.

It is not an unprimeable number, because it can be changed into a prime (666638836663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15150882630 + ... + 15150882673.

It is an arithmetic number, because the mean of its divisors is an integer number (136357943868).

Almost surely, 2^666638836666 is an apocalyptic number.

666638836666 is a deficient number, since it is larger than the sum of its proper divisors (424224714278).

666638836666 is a wasteful number, since it uses less digits than its factorization.

666638836666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30301765316.

The product of its digits is 967458816, while the sum is 70.

The spelling of 666638836666 in words is "six hundred sixty-six billion, six hundred thirty-eight million, eight hundred thirty-six thousand, six hundred sixty-six".