19891812136 has 32 divisors (see below), whose sum is σ = 42648439680. Its totient is φ = 8520436800.

The previous prime is 19891812103. The next prime is 19891812137. The reversal of 19891812136 is 63121819891.

It is a self number, because there is not a number n which added to its sum of digits gives 19891812136.

It is not an unprimeable number, because it can be changed into a prime (19891812137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8781 + ... + 199651.

It is an arithmetic number, because the mean of its divisors is an integer number (1332763740).

Almost surely, 2^19891812136 is an apocalyptic number.

It is an amenable number.

19891812136 is an abundant number, since it is smaller than the sum of its proper divisors (22756627544).

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

19891812136 is a wasteful number, since it uses less digits than its factorization.

19891812136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192745 (or 192741 counting only the distinct ones).

The product of its digits is 186624, while the sum is 49.

The spelling of 19891812136 in words is "nineteen billion, eight hundred ninety-one million, eight hundred twelve thousand, one hundred thirty-six".