199118991 has 16 divisors (see below), whose sum is σ = 267563520. Its totient is φ = 131715360.

The previous prime is 199118989. The next prime is 199119023. The reversal of 199118991 is 199811991.

It is a happy number.

It is not a de Polignac number, because 199118991 - 2¹ = 199118989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 199118991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199118891) 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, 315246 + ... + 315876.

It is an arithmetic number, because the mean of its divisors is an integer number (16722720).

Almost surely, 2^199118991 is an apocalyptic number.

199118991 is a deficient number, since it is larger than the sum of its proper divisors (68444529).

199118991 is a wasteful number, since it uses less digits than its factorization.

199118991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1286.

The product of its digits is 52488, while the sum is 48.

The square root of 199118991 is about 14110.9528735660. The cubic root of 199118991 is about 583.9435883695.

The spelling of 199118991 in words is "one hundred ninety-nine million, one hundred eighteen thousand, nine hundred ninety-one".