18996491 has 4 divisors (see below), whose sum is σ = 19027800. Its totient is φ = 18965184.

The previous prime is 18996473. The next prime is 18996539. The reversal of 18996491 is 19469981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19469981 = 17 ⋅1145293.

It is a cyclic number.

It is not a de Polignac number, because 18996491 - 2²² = 14802187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18996401) 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, 14726 + ... + 15963.

It is an arithmetic number, because the mean of its divisors is an integer number (4756950).

Almost surely, 2^18996491 is an apocalyptic number.

18996491 is a deficient number, since it is larger than the sum of its proper divisors (31309).

18996491 is an equidigital number, since it uses as much as digits as its factorization.

18996491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31308.

The product of its digits is 139968, while the sum is 47.

The square root of 18996491 is about 4358.4964150496. The cubic root of 18996491 is about 266.8237368058.

The spelling of 18996491 in words is "eighteen million, nine hundred ninety-six thousand, four hundred ninety-one".