21991488288 has 384 divisors, whose sum is σ = 78219509760. Its totient is φ = 5235840000.

The previous prime is 21991488287. The next prime is 21991488289. The reversal of 21991488288 is 88288419912.

It is an interprime number because it is at equal distance from previous prime (21991488287) and next prime (21991488289).

It is not an unprimeable number, because it can be changed into a prime (21991488287) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4351363 + ... + 4356413.

It is an arithmetic number, because the mean of its divisors is an integer number (203696640).

Almost surely, 2^21991488288 is an apocalyptic number.

21991488288 is a gapful number since it is divisible by the number (28) 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 21991488288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39109754880).

21991488288 is an abundant number, since it is smaller than the sum of its proper divisors (56228021472).

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

21991488288 is a wasteful number, since it uses less digits than its factorization.

21991488288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5132 (or 5124 counting only the distinct ones).

The product of its digits is 5308416, while the sum is 60.

The spelling of 21991488288 in words is "twenty-one billion, nine hundred ninety-one million, four hundred eighty-eight thousand, two hundred eighty-eight".