20991024288 has 336 divisors, whose sum is σ = 70258214880. Its totient is φ = 6117161472.

The previous prime is 20991024287. The next prime is 20991024311. The reversal of 20991024288 is 88242019902.

It is a happy number.

20991024288 is a `hidden beast` number, since 209 + 9 + 10 + 2 + 428 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (20991024283) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 5760195 + ... + 5763837.

It is an arithmetic number, because the mean of its divisors is an integer number (209101830).

Almost surely, 2^20991024288 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 20991024288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35129107440).

20991024288 is an abundant number, since it is smaller than the sum of its proper divisors (49267190592).

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

20991024288 is a wasteful number, since it uses less digits than its factorization.

20991024288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703 (or 3680 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The spelling of 20991024288 in words is "twenty billion, nine hundred ninety-one million, twenty-four thousand, two hundred eighty-eight".