18489681 has 16 divisors (see below), whose sum is σ = 31305600. Its totient is φ = 10565424.

The previous prime is 18489673. The next prime is 18489703. The reversal of 18489681 is 18698481.

It is not a de Polignac number, because 18489681 - 2³ = 18489673 is a prime.

It is a super-2 number, since 2×18489681² = 683736606963522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (18489281) 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, 48726 + ... + 49103.

It is an arithmetic number, because the mean of its divisors is an integer number (1956600).

Almost surely, 2^18489681 is an apocalyptic number.

It is an amenable number.

18489681 is a deficient number, since it is larger than the sum of its proper divisors (12815919).

18489681 is an equidigital number, since it uses as much as digits as its factorization.

18489681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97845 (or 97839 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 18489681 is about 4299.9629068168. The cubic root of 18489681 is about 264.4294405266.

The spelling of 18489681 in words is "eighteen million, four hundred eighty-nine thousand, six hundred eighty-one".