18109491 has 4 divisors (see below), whose sum is σ = 24145992. Its totient is φ = 12072992.

The previous prime is 18109457. The next prime is 18109499. The reversal of 18109491 is 19490181.

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

It is a cyclic number.

It is not a de Polignac number, because 18109491 - 2¹¹ = 18107443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18109499) 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, 3018246 + ... + 3018251.

It is an arithmetic number, because the mean of its divisors is an integer number (6036498).

Almost surely, 2^18109491 is an apocalyptic number.

18109491 is a deficient number, since it is larger than the sum of its proper divisors (6036501).

18109491 is an equidigital number, since it uses as much as digits as its factorization.

18109491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6036500.

The product of its (nonzero) digits is 2592, while the sum is 33.

The square root of 18109491 is about 4255.5247620006. The cubic root of 18109491 is about 262.6044500433.

The spelling of 18109491 in words is "eighteen million, one hundred nine thousand, four hundred ninety-one".