666696696666 has 96 divisors (see below), whose sum is σ = 1822260017088. Its totient is φ = 159847349760.

The previous prime is 666696696647. The next prime is 666696696697.

666696696666 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is a junction number, because it is equal to n+sod(n) for n = 666696696591 and 666696696600.

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 47 ways as a sum of consecutive naturals, for example, 7886895 + ... + 7970978.

It is an arithmetic number, because the mean of its divisors is an integer number (18981875178).

Almost surely, 2^666696696666 is an apocalyptic number.

666696696666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

666696696666 is an abundant number, since it is smaller than the sum of its proper divisors (1155563320422).

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

666696696666 is a wasteful number, since it uses less digits than its factorization.

666696696666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15857916 (or 15857909 counting only the distinct ones).

The product of its digits is 4897760256, while the sum is 78.

The spelling of 666696696666 in words is "six hundred sixty-six billion, six hundred ninety-six million, six hundred ninety-six thousand, six hundred sixty-six".