18131668 has 6 divisors (see below), whose sum is σ = 31730426. Its totient is φ = 9065832.

The previous prime is 18131651. The next prime is 18131713. The reversal of 18131668 is 86613181.

It can be written as a sum of positive squares in only one way, i.e., 16662724 + 1468944 = 4082^2 + 1212^2 .

It is a congruent number.

It is an unprimeable number.

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, 2266455 + ... + 2266462.

Almost surely, 2^18131668 is an apocalyptic number.

It is an amenable number.

18131668 is a deficient number, since it is larger than the sum of its proper divisors (13598758).

18131668 is a wasteful number, since it uses less digits than its factorization.

18131668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4532921 (or 4532919 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 18131668 is about 4258.1296363544. The cubic root of 18131668 is about 262.7116020191.

It can be divided in two parts, 1813 and 1668, that added together give a square (3481 = 59²).

The spelling of 18131668 in words is "eighteen million, one hundred thirty-one thousand, six hundred sixty-eight".