18957491 has 4 divisors (see below), whose sum is σ = 21665712. Its totient is φ = 16249272.

The previous prime is 18957481. The next prime is 18957527. The reversal of 18957491 is 19475981.

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 18957491 - 2⁶ = 18957427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18957401) 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, 1354100 + ... + 1354113.

It is an arithmetic number, because the mean of its divisors is an integer number (5416428).

Almost surely, 2^18957491 is an apocalyptic number.

18957491 is a deficient number, since it is larger than the sum of its proper divisors (2708221).

18957491 is an equidigital number, since it uses as much as digits as its factorization.

18957491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2708220.

The product of its digits is 90720, while the sum is 44.

The square root of 18957491 is about 4354.0200964166. The cubic root of 18957491 is about 266.6410143727.

The spelling of 18957491 in words is "eighteen million, nine hundred fifty-seven thousand, four hundred ninety-one".