10191818666 has 4 divisors (see below), whose sum is σ = 15287728002. Its totient is φ = 5095909332.

The previous prime is 10191818657. The next prime is 10191818711. The reversal of 10191818666 is 66681819101.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 8142355225 + 2049463441 = 90235^2 + 45271^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 10191818666.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2547954665 + ... + 2547954668.

Almost surely, 2^10191818666 is an apocalyptic number.

10191818666 is a deficient number, since it is larger than the sum of its proper divisors (5095909336).

10191818666 is an equidigital number, since it uses as much as digits as its factorization.

10191818666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5095909335.

The product of its (nonzero) digits is 124416, while the sum is 47.

The spelling of 10191818666 in words is "ten billion, one hundred ninety-one million, eight hundred eighteen thousand, six hundred sixty-six".