18208091 has 4 divisors (see below), whose sum is σ = 19863384. Its totient is φ = 16552800.

The previous prime is 18208081. The next prime is 18208103. The reversal of 18208091 is 19080281.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 18208091 - 2¹⁴ = 18191707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18208051) 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, 827630 + ... + 827651.

It is an arithmetic number, because the mean of its divisors is an integer number (4965846).

Almost surely, 2^18208091 is an apocalyptic number.

18208091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18208091 is a deficient number, since it is larger than the sum of its proper divisors (1655293).

18208091 is a wasteful number, since it uses less digits than its factorization.

18208091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1655292.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 18208091 is about 4267.0939759982. The cubic root of 18208091 is about 263.0801848926.

The spelling of 18208091 in words is "eighteen million, two hundred eight thousand, ninety-one".