19999801836 has 36 divisors (see below), whose sum is σ = 57777206032. Its totient is φ = 5714229024.

The previous prime is 19999801813. The next prime is 19999801837. The reversal of 19999801836 is 63810899991.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (19999801837) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39681895 + ... + 39682398.

Almost surely, 2^19999801836 is an apocalyptic number.

It is an amenable number.

19999801836 is an abundant number, since it is smaller than the sum of its proper divisors (37777404196).

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

19999801836 is a wasteful number, since it uses less digits than its factorization.

19999801836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79364310 (or 79364305 counting only the distinct ones).

The product of its (nonzero) digits is 7558272, while the sum is 63.

The spelling of 19999801836 in words is "nineteen billion, nine hundred ninety-nine million, eight hundred one thousand, eight hundred thirty-six".