20784291840 has 336 divisors, whose sum is σ = 77607843768. Its totient is φ = 5114953728.

The previous prime is 20784291833. The next prime is 20784291901. The reversal of 20784291840 is 4819248702.

20784291840 is a `hidden beast` number, since 207 + 8 + 429 + 18 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6106484736 + 14677807104 = 78144^2 + 121152^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4790152 + ... + 4794488.

Almost surely, 2^20784291840 is an apocalyptic number.

20784291840 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 20784291840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38803921884).

20784291840 is an abundant number, since it is smaller than the sum of its proper divisors (56823551928).

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

20784291840 is a wasteful number, since it uses less digits than its factorization.

20784291840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4387 (or 4360 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 20784291840 in words is "twenty billion, seven hundred eighty-four million, two hundred ninety-one thousand, eight hundred forty".