18791121 has 4 divisors (see below), whose sum is σ = 25054832. Its totient is φ = 12527412.

The previous prime is 18791107. The next prime is 18791141. The reversal of 18791121 is 12119781.

18791121 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18791121 - 2⁵ = 18791089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18791141) 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, 3131851 + ... + 3131856.

It is an arithmetic number, because the mean of its divisors is an integer number (6263708).

Almost surely, 2^18791121 is an apocalyptic number.

It is an amenable number.

18791121 is a deficient number, since it is larger than the sum of its proper divisors (6263711).

18791121 is an equidigital number, since it uses as much as digits as its factorization.

18791121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6263710.

The product of its digits is 1008, while the sum is 30.

The square root of 18791121 is about 4334.8726624896. The cubic root of 18791121 is about 265.8587119721.

The spelling of 18791121 in words is "eighteen million, seven hundred ninety-one thousand, one hundred twenty-one".