18198281 has 4 divisors (see below), whose sum is σ = 18378564. Its totient is φ = 18018000.

The previous prime is 18198263. The next prime is 18198287. The reversal of 18198281 is 18289181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18289181 = 101 ⋅181081.

It can be written as a sum of positive squares in 2 ways, for example, as 11868025 + 6330256 = 3445^2 + 2516^2 .

It is a cyclic number.

It is not a de Polignac number, because 18198281 - 2⁶ = 18198217 is a prime.

It is a super-2 number, since 2×18198281² = 662354862709922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18198287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89990 + ... + 90191.

It is an arithmetic number, because the mean of its divisors is an integer number (4594641).

Almost surely, 2^18198281 is an apocalyptic number.

It is an amenable number.

18198281 is a deficient number, since it is larger than the sum of its proper divisors (180283).

18198281 is a wasteful number, since it uses less digits than its factorization.

18198281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180282.

The product of its digits is 9216, while the sum is 38.

The square root of 18198281 is about 4265.9443268754. The cubic root of 18198281 is about 263.0329297055.

The spelling of 18198281 in words is "eighteen million, one hundred ninety-eight thousand, two hundred eighty-one".