1998198181828 has 6 divisors (see below), whose sum is σ = 3496846818206. Its totient is φ = 999099090912.

The previous prime is 1998198181717. The next prime is 1998198181829. The reversal of 1998198181828 is 8281818918991.

It can be written as a sum of positive squares in only one way, i.e., 1875535728004 + 122662453824 = 1369502^2 + 350232^2 .

It is not an unprimeable number, because it can be changed into a prime (1998198181829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249774772725 + ... + 249774772732.

Almost surely, 2^{1998198181828} is an apocalyptic number.

It is an amenable number.

1998198181828 is a deficient number, since it is larger than the sum of its proper divisors (1498648636378).

1998198181828 is a wasteful number, since it uses less digits than its factorization.

1998198181828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499549545461 (or 499549545459 counting only the distinct ones).

The product of its digits is 47775744, while the sum is 73.

The spelling of 1998198181828 in words is "one trillion, nine hundred ninety-eight billion, one hundred ninety-eight million, one hundred eighty-one thousand, eight hundred twenty-eight".