18881818 has 8 divisors (see below), whose sum is σ = 28787220. Its totient is φ = 9286080.

The previous prime is 18881809. The next prime is 18881861. The reversal of 18881818 is 81818881.

It can be written as a sum of positive squares in 2 ways, for example, as 18774889 + 106929 = 4333^2 + 327^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77263 + ... + 77506.

Almost surely, 2^18881818 is an apocalyptic number.

18881818 is a deficient number, since it is larger than the sum of its proper divisors (9905402).

18881818 is a wasteful number, since it uses less digits than its factorization.

18881818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154832.

The product of its digits is 32768, while the sum is 43.

The square root of 18881818 is about 4345.3213920261. The cubic root of 18881818 is about 266.2857558128.

The spelling of 18881818 in words is "eighteen million, eight hundred eighty-one thousand, eight hundred eighteen".