18117812 has 6 divisors (see below), whose sum is σ = 31706178. Its totient is φ = 9058904.

The previous prime is 18117809. The next prime is 18117817. The reversal of 18117812 is 21871181.

It can be written as a sum of positive squares in only one way, i.e., 18011536 + 106276 = 4244^2 + 326^2 .

It is a super-2 number, since 2×18117812² = 656510223334688, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18117817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2264723 + ... + 2264730.

It is an arithmetic number, because the mean of its divisors is an integer number (5284363).

Almost surely, 2^18117812 is an apocalyptic number.

It is an amenable number.

18117812 is a deficient number, since it is larger than the sum of its proper divisors (13588366).

18117812 is a wasteful number, since it uses less digits than its factorization.

18117812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4529457 (or 4529455 counting only the distinct ones).

The product of its digits is 896, while the sum is 29.

The square root of 18117812 is about 4256.5023199806. The cubic root of 18117812 is about 262.6446646291.

Adding to 18117812 its reverse (21871181), we get a palindrome (39988993).

The spelling of 18117812 in words is "eighteen million, one hundred seventeen thousand, eight hundred twelve".