18213898 has 4 divisors (see below), whose sum is σ = 27320850. Its totient is φ = 9106948.

The previous prime is 18213893. The next prime is 18213911. The reversal of 18213898 is 89831281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89831281 = 17 ⋅5284193.

It can be written as a sum of positive squares in only one way, i.e., 14265729 + 3948169 = 3777^2 + 1987^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 18213898.

It is not an unprimeable number, because it can be changed into a prime (18213893) 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 as a sum of consecutive naturals, namely, 4553473 + ... + 4553476.

Almost surely, 2^18213898 is an apocalyptic number.

18213898 is a deficient number, since it is larger than the sum of its proper divisors (9106952).

18213898 is an equidigital number, since it uses as much as digits as its factorization.

18213898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9106951.

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

The square root of 18213898 is about 4267.7743614207. The cubic root of 18213898 is about 263.1081494617.

The spelling of 18213898 in words is "eighteen million, two hundred thirteen thousand, eight hundred ninety-eight".