1981998181836 has 60 divisors (see below), whose sum is σ = 5321370859728. Its totient is φ = 642810217248.

The previous prime is 1981998181819. The next prime is 1981998181841. The reversal of 1981998181836 is 6381818991891.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 82653936 + ... + 82677911.

Almost surely, 2^{1981998181836} is an apocalyptic number.

It is an amenable number.

1981998181836 is an abundant number, since it is smaller than the sum of its proper divisors (3339372677892).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1981998181836 is a wasteful number, since it uses less digits than its factorization.

1981998181836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165331900 (or 165331889 counting only the distinct ones).

The product of its digits is 53747712, while the sum is 72.

The spelling of 1981998181836 in words is "one trillion, nine hundred eighty-one billion, nine hundred ninety-eight million, one hundred eighty-one thousand, eight hundred thirty-six".