18297981 has 20 divisors (see below), whose sum is σ = 29438332. Its totient is φ = 11259648.

The previous prime is 18297973. The next prime is 18298009. The reversal of 18297981 is 18979281.

It can be written as a sum of positive squares in 2 ways, for example, as 1822500 + 16475481 = 1350^2 + 4059^2 .

It is not a de Polignac number, because 18297981 - 2³ = 18297973 is a prime.

It is a super-2 number, since 2×18297981² = 669632217352722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18297911) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7636 + ... + 9741.

Almost surely, 2^18297981 is an apocalyptic number.

It is an amenable number.

18297981 is a deficient number, since it is larger than the sum of its proper divisors (11140351).

18297981 is a wasteful number, since it uses less digits than its factorization.

18297981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17402 (or 17393 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 18297981 is about 4277.6139376994. The cubic root of 18297981 is about 263.5124005941.

The spelling of 18297981 in words is "eighteen million, two hundred ninety-seven thousand, nine hundred eighty-one".