18218943898 has 4 divisors (see below), whose sum is σ = 27328415850. Its totient is φ = 9109471948.

The previous prime is 18218943863. The next prime is 18218943907. The reversal of 18218943898 is 89834981281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12677183649 + 5541760249 = 112593^2 + 74443^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4554735973 + ... + 4554735976.

Almost surely, 2^18218943898 is an apocalyptic number.

18218943898 is a deficient number, since it is larger than the sum of its proper divisors (9109471952).

18218943898 is an equidigital number, since it uses as much as digits as its factorization.

18218943898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9109471951.

The product of its digits is 7962624, while the sum is 61.

The spelling of 18218943898 in words is "eighteen billion, two hundred eighteen million, nine hundred forty-three thousand, eight hundred ninety-eight".