18081816 has 16 divisors (see below), whose sum is σ = 45204600. Its totient is φ = 6027264.

The previous prime is 18081781. The next prime is 18081821. The reversal of 18081816 is 61818081.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 376681 + ... + 376728.

Almost surely, 2^18081816 is an apocalyptic number.

It is an amenable number.

18081816 is an abundant number, since it is smaller than the sum of its proper divisors (27122784).

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

18081816 is a wasteful number, since it uses less digits than its factorization.

18081816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 753418 (or 753414 counting only the distinct ones).

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

The square root of 18081816 is about 4252.2718633690. The cubic root of 18081816 is about 262.4706107687.

Adding to 18081816 its reverse (61818081), we get a palindrome (79899897).

The spelling of 18081816 in words is "eighteen million, eighty-one thousand, eight hundred sixteen".