18168491 has 4 divisors (see below), whose sum is σ = 19820184. Its totient is φ = 16516800.

The previous prime is 18168487. The next prime is 18168523. The reversal of 18168491 is 19486181.

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 18168491 - 2² = 18168487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18168481) 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, 825830 + ... + 825851.

It is an arithmetic number, because the mean of its divisors is an integer number (4955046).

Almost surely, 2^18168491 is an apocalyptic number.

18168491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18168491 is a deficient number, since it is larger than the sum of its proper divisors (1651693).

18168491 is a wasteful number, since it uses less digits than its factorization.

18168491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651692.

The product of its digits is 13824, while the sum is 38.

The square root of 18168491 is about 4262.4512900443. The cubic root of 18168491 is about 262.8893258400.

The spelling of 18168491 in words is "eighteen million, one hundred sixty-eight thousand, four hundred ninety-one".