21697808832 has 336 divisors, whose sum is σ = 76230236160. Its totient is φ = 5759410176.

The previous prime is 21697808801. The next prime is 21697808837. The reversal of 21697808832 is 23880879612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×21697808832² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697808837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5412973 + ... + 5416979.

Almost surely, 2^21697808832 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 21697808832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38115118080).

21697808832 is an abundant number, since it is smaller than the sum of its proper divisors (54532427328).

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

21697808832 is a wasteful number, since it uses less digits than its factorization.

21697808832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4128 (or 4115 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 21697808832 in words is "twenty-one billion, six hundred ninety-seven million, eight hundred eight thousand, eight hundred thirty-two".