20991900288 has 256 divisors, whose sum is σ = 61128224640. Its totient is φ = 6356336640.

The previous prime is 20991900253. The next prime is 20991900289. The reversal of 20991900288 is 88200919902.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (20991900289) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 28637970 + ... + 28638702.

Almost surely, 2^20991900288 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 20991900288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30564112320).

20991900288 is an abundant number, since it is smaller than the sum of its proper divisors (40136324352).

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

20991900288 is a wasteful number, since it uses less digits than its factorization.

20991900288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915 (or 903 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 48.

The spelling of 20991900288 in words is "twenty billion, nine hundred ninety-one million, nine hundred thousand, two hundred eighty-eight".