21331634688 has 640 divisors, whose sum is σ = 80368189440. Its totient is φ = 5434490880.

The previous prime is 21331634659. The next prime is 21331634707. The reversal of 21331634688 is 88643613312.

21331634688 is a `hidden beast` number, since 2 + 1 + 3 + 3 + 1 + 634 + 6 + 8 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 38997231 + ... + 38997777.

It is an arithmetic number, because the mean of its divisors is an integer number (125575296).

Almost surely, 2^21331634688 is an apocalyptic number.

21331634688 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 21331634688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40184094720).

21331634688 is an abundant number, since it is smaller than the sum of its proper divisors (59036554752).

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

21331634688 is a wasteful number, since it uses less digits than its factorization.

21331634688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625 (or 603 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

It can be divided in two parts, 213316 and 34688, that added together give a square (248004 = 498²).

The spelling of 21331634688 in words is "twenty-one billion, three hundred thirty-one million, six hundred thirty-four thousand, six hundred eighty-eight".