21135218688 has 288 divisors, whose sum is σ = 64433940480. Its totient is φ = 6664273920.

The previous prime is 21135218633. The next prime is 21135218717. The reversal of 21135218688 is 88681253112.

21135218688 is a `hidden beast` number, since 2 + 113 + 521 + 8 + 6 + 8 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26855031 + ... + 26855817.

It is an arithmetic number, because the mean of its divisors is an integer number (223728960).

Almost surely, 2^21135218688 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 21135218688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32216970240).

21135218688 is an abundant number, since it is smaller than the sum of its proper divisors (43298721792).

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

21135218688 is a wasteful number, since it uses less digits than its factorization.

21135218688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 893 (or 870 counting only the distinct ones).

The product of its digits is 184320, while the sum is 45.

The spelling of 21135218688 in words is "twenty-one billion, one hundred thirty-five million, two hundred eighteen thousand, six hundred eighty-eight".