21115326056 has 64 divisors (see below), whose sum is σ = 44553024000. Its totient is φ = 9297365760.

The previous prime is 21115326047. The next prime is 21115326059. The reversal of 21115326056 is 65062351112.

It is not an unprimeable number, because it can be changed into a prime (21115326059) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 731465 + ... + 759783.

It is an arithmetic number, because the mean of its divisors is an integer number (696141000).

Almost surely, 2^21115326056 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 21115326056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22276512000).

21115326056 is an abundant number, since it is smaller than the sum of its proper divisors (23437697944).

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

21115326056 is a wasteful number, since it uses less digits than its factorization.

21115326056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28602 (or 28598 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

Adding to 21115326056 its reverse (65062351112), we get a palindrome (86177677168).

The spelling of 21115326056 in words is "twenty-one billion, one hundred fifteen million, three hundred twenty-six thousand, fifty-six".