18199091 has 4 divisors (see below), whose sum is σ = 18209184. Its totient is φ = 18189000.

The previous prime is 18199073. The next prime is 18199117. The reversal of 18199091 is 19099181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19099181 = 43 ⋅444167.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18199091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18199031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1520 + ... + 6221.

It is an arithmetic number, because the mean of its divisors is an integer number (4552296).

Almost surely, 2^18199091 is an apocalyptic number.

18199091 is a deficient number, since it is larger than the sum of its proper divisors (10093).

18199091 is an equidigital number, since it uses as much as digits as its factorization.

18199091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10092.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 18199091 is about 4266.0392637668. The cubic root of 18199091 is about 263.0368321531.

The spelling of 18199091 in words is "eighteen million, one hundred ninety-nine thousand, ninety-one".