18213091 has 4 divisors (see below), whose sum is σ = 19614112. Its totient is φ = 16812072.

The previous prime is 18213067. The next prime is 18213101. The reversal of 18213091 is 19031281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19031281 = 23 ⋅827447.

It is a cyclic number.

It is not a de Polignac number, because 18213091 - 2¹⁷ = 18082019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18013091) 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 3 ways as a sum of consecutive naturals, for example, 700491 + ... + 700516.

It is an arithmetic number, because the mean of its divisors is an integer number (4903528).

Almost surely, 2^18213091 is an apocalyptic number.

18213091 is a deficient number, since it is larger than the sum of its proper divisors (1401021).

18213091 is a wasteful number, since it uses less digits than its factorization.

18213091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401020.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 18213091 is about 4267.6798146065. The cubic root of 18213091 is about 263.1042635754.

The spelling of 18213091 in words is "eighteen million, two hundred thirteen thousand, ninety-one".