18689881 has 8 divisors (see below), whose sum is σ = 21468800. Its totient is φ = 15938208.

The previous prime is 18689873. The next prime is 18689887. The reversal of 18689881 is 18898681.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18689881 - 2³ = 18689873 is a prime.

It is a super-2 number, since 2×18689881² = 698623303588322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18689887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5316 + ... + 8101.

It is an arithmetic number, because the mean of its divisors is an integer number (2683600).

Almost surely, 2^18689881 is an apocalyptic number.

It is an amenable number.

18689881 is a deficient number, since it is larger than the sum of its proper divisors (2778919).

18689881 is a wasteful number, since it uses less digits than its factorization.

18689881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13623.

The product of its digits is 221184, while the sum is 49.

The square root of 18689881 is about 4323.1795012467. The cubic root of 18689881 is about 265.3804006397.

The spelling of 18689881 in words is "eighteen million, six hundred eighty-nine thousand, eight hundred eighty-one".