21689330868 has 72 divisors (see below), whose sum is σ = 55632595200. Its totient is φ = 7123761216.

The previous prime is 21689330867. The next prime is 21689330879. The reversal of 21689330868 is 86803398612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21689330867) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1440105 + ... + 1455087.

Almost surely, 2^21689330868 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 21689330868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27816297600).

21689330868 is an abundant number, since it is smaller than the sum of its proper divisors (33943264332).

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

21689330868 is a wasteful number, since it uses less digits than its factorization.

21689330868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15581 (or 15576 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 21689330868 in words is "twenty-one billion, six hundred eighty-nine million, three hundred thirty thousand, eight hundred sixty-eight".