18391449 has 16 divisors (see below), whose sum is σ = 25921280. Its totient is φ = 11566800.

The previous prime is 18391447. The next prime is 18391459. The reversal of 18391449 is 94419381.

It is not a de Polignac number, because 18391449 - 2¹ = 18391447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18391441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16974 + ... + 18024.

It is an arithmetic number, because the mean of its divisors is an integer number (1620080).

Almost surely, 2^18391449 is an apocalyptic number.

18391449 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18391449 is a deficient number, since it is larger than the sum of its proper divisors (7529831).

18391449 is a wasteful number, since it uses less digits than its factorization.

18391449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380.

The product of its digits is 31104, while the sum is 39.

The square root of 18391449 is about 4288.5252709993. The cubic root of 18391449 is about 263.9603217457.

The spelling of 18391449 in words is "eighteen million, three hundred ninety-one thousand, four hundred forty-nine".