20171788920 has 96 divisors (see below), whose sum is σ = 65577489120. Its totient is φ = 5377570560.

The previous prime is 20171788823. The next prime is 20171788937. The reversal of 20171788920 is 2988717102.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1744197 + ... + 1755723.

It is an arithmetic number, because the mean of its divisors is an integer number (683098845).

Almost surely, 2^20171788920 is an apocalyptic number.

20171788920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20171788920 is an abundant number, since it is smaller than the sum of its proper divisors (45405700200).

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

20171788920 is a wasteful number, since it uses less digits than its factorization.

20171788920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16405 (or 16398 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The spelling of 20171788920 in words is "twenty billion, one hundred seventy-one million, seven hundred eighty-eight thousand, nine hundred twenty".