199818181836 has 144 divisors (see below), whose sum is σ = 622540609600. Its totient is φ = 52624359936.

The previous prime is 199818181817. The next prime is 199818181859. The reversal of 199818181836 is 638181818991.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2279670 + ... + 2365698.

Almost surely, 2^199818181836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 199818181836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311270304800).

199818181836 is an abundant number, since it is smaller than the sum of its proper divisors (422722427764).

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

199818181836 is a wasteful number, since it uses less digits than its factorization.

199818181836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86768 (or 86763 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 63.

The spelling of 199818181836 in words is "one hundred ninety-nine billion, eight hundred eighteen million, one hundred eighty-one thousand, eight hundred thirty-six".