18181806 has 32 divisors (see below), whose sum is σ = 38685600. Its totient is φ = 5677056.

The previous prime is 18181783. The next prime is 18181817. The reversal of 18181806 is 60818181.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40270 + ... + 40718.

It is an arithmetic number, because the mean of its divisors is an integer number (1208925).

Almost surely, 2^18181806 is an apocalyptic number.

18181806 is an abundant number, since it is smaller than the sum of its proper divisors (20503794).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18181806 is a wasteful number, since it uses less digits than its factorization.

18181806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868.

The product of its (nonzero) digits is 3072, while the sum is 33.

The square root of 18181806 is about 4264.0128986672. The cubic root of 18181806 is about 262.9535307066.

Adding to 18181806 its reverse (60818181), we get a palindrome (78999987).

The spelling of 18181806 in words is "eighteen million, one hundred eighty-one thousand, eight hundred six".