18993091 has 8 divisors (see below), whose sum is σ = 20543040. Its totient is φ = 17455872.

The previous prime is 18993089. The next prime is 18993113. The reversal of 18993091 is 19039981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18993091 - 2¹ = 18993089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18993001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51 + ... + 6163.

It is an arithmetic number, because the mean of its divisors is an integer number (2567880).

Almost surely, 2^18993091 is an apocalyptic number.

18993091 is a deficient number, since it is larger than the sum of its proper divisors (1549949).

18993091 is a wasteful number, since it uses less digits than its factorization.

18993091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6365.

The product of its (nonzero) digits is 17496, while the sum is 40.

The square root of 18993091 is about 4358.1063548289. The cubic root of 18993091 is about 266.8078171142.

The spelling of 18993091 in words is "eighteen million, nine hundred ninety-three thousand, ninety-one".