20051871840 has 768 divisors, whose sum is σ = 94250096640. Its totient is φ = 3845283840.

The previous prime is 20051871839. The next prime is 20051871857. The reversal of 20051871840 is 4817815002.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20051871795 and 20051871804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4322002 + ... + 4326638.

It is an arithmetic number, because the mean of its divisors is an integer number (122721480).

Almost surely, 2^20051871840 is an apocalyptic number.

20051871840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20051871840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47125048320).

20051871840 is an abundant number, since it is smaller than the sum of its proper divisors (74198224800).

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

20051871840 is a wasteful number, since it uses less digits than its factorization.

20051871840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4692 (or 4678 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 36.

The spelling of 20051871840 in words is "twenty billion, fifty-one million, eight hundred seventy-one thousand, eight hundred forty".