18000018 has 24 divisors (see below), whose sum is σ = 39390156. Its totient is φ = 5940000.

The previous prime is 17999987. The next prime is 18000041. The reversal of 18000018 is 81000081.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12510369 + 5489649 = 3537^2 + 2343^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3133 + ... + 6768.

Almost surely, 2^18000018 is an apocalyptic number.

18000018 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18000018 is an abundant number, since it is smaller than the sum of its proper divisors (21390138).

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

18000018 is a wasteful number, since it uses less digits than its factorization.

18000018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10010 (or 10007 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 18000018 is about 4242.6428084391. The cubic root of 18000018 is about 262.0742267789.

18000018 divided by its sum of digits (18) gives a palindrome (1000001).

Adding to 18000018 its reverse (81000081), we get a palindrome (99000099).

It can be divided in two parts, 180000 and 18, that multiplied together give a square (3240000 = 1800²).

The spelling of 18000018 in words is "eighteen million, eighteen", and thus it is an aban number and an uban number.