20684840400 has 1080 divisors, whose sum is σ = 89485460064. Its totient is φ = 4572288000.

The previous prime is 20684840399. The next prime is 20684840413. The reversal of 20684840400 is 404848602.

20684840400 is a `hidden beast` number, since 206 + 8 + 4 + 8 + 40 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (1080).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 204800350 + ... + 204800450.

Almost surely, 2^20684840400 is an apocalyptic number.

20684840400 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 20684840400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44742730032).

20684840400 is an abundant number, since it is smaller than the sum of its proper divisors (68800619664).

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

20684840400 is a wasteful number, since it uses less digits than its factorization.

20684840400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 36.

The spelling of 20684840400 in words is "twenty billion, six hundred eighty-four million, eight hundred forty thousand, four hundred".