18611491 has 4 divisors (see below), whose sum is σ = 18927000. Its totient is φ = 18295984.

The previous prime is 18611471. The next prime is 18611497. The reversal of 18611491 is 19411681.

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 18611491 - 2⁵ = 18611459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18611497) 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, 157666 + ... + 157783.

It is an arithmetic number, because the mean of its divisors is an integer number (4731750).

Almost surely, 2^18611491 is an apocalyptic number.

18611491 is a deficient number, since it is larger than the sum of its proper divisors (315509).

18611491 is an equidigital number, since it uses as much as digits as its factorization.

18611491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315508.

The product of its digits is 1728, while the sum is 31.

The square root of 18611491 is about 4314.1037307881. The cubic root of 18611491 is about 265.0088569485.

The spelling of 18611491 in words is "eighteen million, six hundred eleven thousand, four hundred ninety-one".