18398281 has 16 divisors (see below), whose sum is σ = 20801088. Its totient is φ = 16128000.

The previous prime is 18398279. The next prime is 18398309. The reversal of 18398281 is 18289381.

It is a cyclic number.

It is not a de Polignac number, because 18398281 - 2¹ = 18398279 is a prime.

It is a super-2 number, since 2×18398281² = 676993487509922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18398201) 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 in 15 ways as a sum of consecutive naturals, for example, 45681 + ... + 46081.

It is an arithmetic number, because the mean of its divisors is an integer number (1300068).

Almost surely, 2^18398281 is an apocalyptic number.

18398281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18398281 is a deficient number, since it is larger than the sum of its proper divisors (2402807).

18398281 is a wasteful number, since it uses less digits than its factorization.

18398281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552.

The product of its digits is 27648, while the sum is 40.

The square root of 18398281 is about 4289.3217412547. The cubic root of 18398281 is about 263.9930027607.

Subtracting from 18398281 its reverse (18289381), we obtain a square (108900 = 330²).

The spelling of 18398281 in words is "eighteen million, three hundred ninety-eight thousand, two hundred eighty-one".