1991165199 has 16 divisors (see below), whose sum is σ = 2713886208. Its totient is φ = 1297996352.

The previous prime is 1991165153. The next prime is 1991165219. The reversal of 1991165199 is 9915611991.

It is a cyclic number.

It is not a de Polignac number, because 1991165199 - 2⁸ = 1991164943 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991165129) 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, 161419 + ... + 173315.

It is an arithmetic number, because the mean of its divisors is an integer number (169617888).

Almost surely, 2^1991165199 is an apocalyptic number.

1991165199 is a deficient number, since it is larger than the sum of its proper divisors (722721009).

1991165199 is a wasteful number, since it uses less digits than its factorization.

1991165199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13134.

The product of its digits is 196830, while the sum is 51.

The square root of 1991165199 is about 44622.4741470035. The cubic root of 1991165199 is about 1258.0631195039.

The spelling of 1991165199 in words is "one billion, nine hundred ninety-one million, one hundred sixty-five thousand, one hundred ninety-nine".