20684474880 has 320 divisors, whose sum is σ = 67881369600. Its totient is φ = 5371412480.

The previous prime is 20684474807. The next prime is 20684474891. The reversal of 20684474880 is 8847448602.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×20684474880² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 86545801 + ... + 86546039.

It is an arithmetic number, because the mean of its divisors is an integer number (212129280).

Almost surely, 2^20684474880 is an apocalyptic number.

20684474880 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 20684474880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33940684800).

20684474880 is an abundant number, since it is smaller than the sum of its proper divisors (47196894720).

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

20684474880 is a wasteful number, since it uses less digits than its factorization.

20684474880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515 (or 499 counting only the distinct ones).

The product of its (nonzero) digits is 2752512, while the sum is 51.

The spelling of 20684474880 in words is "twenty billion, six hundred eighty-four million, four hundred seventy-four thousand, eight hundred eighty".