9191691666 has 24 divisors (see below), whose sum is σ = 20195832384. Its totient is φ = 3020743320.

The previous prime is 9191691643. The next prime is 9191691667. The reversal of 9191691666 is 6661961919.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (9191691667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3594846 + ... + 3597401.

It is an arithmetic number, because the mean of its divisors is an integer number (841493016).

Almost surely, 2^9191691666 is an apocalyptic number.

9191691666 is an abundant number, since it is smaller than the sum of its proper divisors (11004140718).

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

9191691666 is a wasteful number, since it uses less digits than its factorization.

9191691666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7192326 (or 7192323 counting only the distinct ones).

The product of its digits is 944784, while the sum is 54.

The square root of 9191691666 is about 95873.3104988036. The cubic root of 9191691666 is about 2094.7481515350.

The spelling of 9191691666 in words is "nine billion, one hundred ninety-one million, six hundred ninety-one thousand, six hundred sixty-six".