21653443332 has 72 divisors (see below), whose sum is σ = 56788123392. Its totient is φ = 6949454400.

The previous prime is 21653443319. The next prime is 21653443379. The reversal of 21653443332 is 23334435612.

21653443332 is a `hidden beast` number, since 2 + 165 + 34 + 433 + 32 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 170607 + ... + 269097.

It is an arithmetic number, because the mean of its divisors is an integer number (788723936).

Almost surely, 2^21653443332 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 21653443332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28394061696).

21653443332 is an abundant number, since it is smaller than the sum of its proper divisors (35134680060).

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

21653443332 is a wasteful number, since it uses less digits than its factorization.

21653443332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98729 (or 98724 counting only the distinct ones).

The product of its digits is 155520, while the sum is 36.

Adding to 21653443332 its reverse (23334435612), we get a palindrome (44987878944).

The spelling of 21653443332 in words is "twenty-one billion, six hundred fifty-three million, four hundred forty-three thousand, three hundred thirty-two".