18120681 has 6 divisors (see below), whose sum is σ = 26174330. Its totient is φ = 12080448.

The previous prime is 18120653. The next prime is 18120689. The reversal of 18120681 is 18602181.

It can be written as a sum of positive squares in only one way, i.e., 10830681 + 7290000 = 3291^2 + 2700^2 .

It is not a de Polignac number, because 18120681 - 2⁵ = 18120649 is a prime.

It is a super-2 number, since 2×18120681² = 656718159807522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18120689) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1006696 + ... + 1006713.

Almost surely, 2^18120681 is an apocalyptic number.

It is an amenable number.

18120681 is a deficient number, since it is larger than the sum of its proper divisors (8053649).

18120681 is a wasteful number, since it uses less digits than its factorization.

18120681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2013415 (or 2013412 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 18120681 is about 4256.8393204348. The cubic root of 18120681 is about 262.6585273731.

The spelling of 18120681 in words is "eighteen million, one hundred twenty thousand, six hundred eighty-one".