1998198181844 has 48 divisors (see below), whose sum is σ = 3581393227776. Its totient is φ = 975227752800.

The previous prime is 1998198181843. The next prime is 1998198181853. The reversal of 1998198181844 is 4481818918991.

It is a Harshad number since it is a multiple of its sum of digits (71).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998198181843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234333509 + ... + 234342035.

It is an arithmetic number, because the mean of its divisors is an integer number (74612358912).

Almost surely, 2^{1998198181844} is an apocalyptic number.

It is an amenable number.

1998198181844 is a deficient number, since it is larger than the sum of its proper divisors (1583195045932).

1998198181844 is a wasteful number, since it uses less digits than its factorization.

1998198181844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16716 (or 16714 counting only the distinct ones).

The product of its digits is 47775744, while the sum is 71.

The spelling of 1998198181844 in words is "one trillion, nine hundred ninety-eight billion, one hundred ninety-eight million, one hundred eighty-one thousand, eight hundred forty-four".