20978800128 has 720 divisors, whose sum is σ = 74763786240. Its totient is φ = 5607014400.

The previous prime is 20978800121. The next prime is 20978800133. The reversal of 20978800128 is 82100887902.

It is a happy number.

It is a super-2 number, since 2×20978800128² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20978800121) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 265554393 + ... + 265554471.

It is an arithmetic number, because the mean of its divisors is an integer number (103838592).

Almost surely, 2^20978800128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20978800128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37381893120).

20978800128 is an abundant number, since it is smaller than the sum of its proper divisors (53784986112).

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

20978800128 is a wasteful number, since it uses less digits than its factorization.

20978800128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 20978800128 in words is "twenty billion, nine hundred seventy-eight million, eight hundred thousand, one hundred twenty-eight".