18981489 has 4 divisors (see below), whose sum is σ = 25308656. Its totient is φ = 12654324.

The previous prime is 18981451. The next prime is 18981493. The reversal of 18981489 is 98418981.

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 18981489 - 2¹² = 18977393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18981439) 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, 3163579 + ... + 3163584.

It is an arithmetic number, because the mean of its divisors is an integer number (6327164).

Almost surely, 2^18981489 is an apocalyptic number.

It is an amenable number.

18981489 is a deficient number, since it is larger than the sum of its proper divisors (6327167).

18981489 is an equidigital number, since it uses as much as digits as its factorization.

18981489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6327166.

The product of its digits is 165888, while the sum is 48.

The square root of 18981489 is about 4356.7750687865. The cubic root of 18981489 is about 266.7534792007.

The spelling of 18981489 in words is "eighteen million, nine hundred eighty-one thousand, four hundred eighty-nine".