18521091 has 12 divisors (see below), whose sum is σ = 26866840. Its totient is φ = 12294720.

The previous prime is 18521071. The next prime is 18521093. The reversal of 18521091 is 19012581.

It is not a de Polignac number, because 18521091 - 2²² = 14326787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18521093) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2101 + ... + 6438.

Almost surely, 2^18521091 is an apocalyptic number.

18521091 is a deficient number, since it is larger than the sum of its proper divisors (8345749).

18521091 is a wasteful number, since it uses less digits than its factorization.

18521091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8786 (or 8783 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 18521091 is about 4303.6137140780. The cubic root of 18521091 is about 264.5790921069.

The spelling of 18521091 in words is "eighteen million, five hundred twenty-one thousand, ninety-one".