18881289 has 16 divisors (see below), whose sum is σ = 31968640. Its totient is φ = 10789200.

The previous prime is 18881287. The next prime is 18881293. The reversal of 18881289 is 98218881.

It is not a de Polignac number, because 18881289 - 2¹ = 18881287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18881281) 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, 49762 + ... + 50139.

It is an arithmetic number, because the mean of its divisors is an integer number (1998040).

Almost surely, 2^18881289 is an apocalyptic number.

It is an amenable number.

18881289 is a deficient number, since it is larger than the sum of its proper divisors (13087351).

18881289 is an equidigital number, since it uses as much as digits as its factorization.

18881289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99917 (or 99911 counting only the distinct ones).

The product of its digits is 73728, while the sum is 45.

The square root of 18881289 is about 4345.2605215338. The cubic root of 18881289 is about 266.2832690028.

The spelling of 18881289 in words is "eighteen million, eight hundred eighty-one thousand, two hundred eighty-nine".