1998198181827 has 12 divisors (see below), whose sum is σ = 2894556428400. Its totient is φ = 1328315121648.

The previous prime is 1998198181717. The next prime is 1998198181829. The reversal of 1998198181827 is 7281818918991.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-1998198181827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1998198181829) 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 11 ways as a sum of consecutive naturals, for example, 318079983 + ... + 318086264.

It is an arithmetic number, because the mean of its divisors is an integer number (241213035700).

Almost surely, 2^{1998198181827} is an apocalyptic number.

1998198181827 is a deficient number, since it is larger than the sum of its proper divisors (896358246573).

1998198181827 is a wasteful number, since it uses less digits than its factorization.

1998198181827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636166602 (or 636166599 counting only the distinct ones).

The product of its digits is 41803776, while the sum is 72.

The spelling of 1998198181827 in words is "one trillion, nine hundred ninety-eight billion, one hundred ninety-eight million, one hundred eighty-one thousand, eight hundred twenty-seven".