21333433520 has 80 divisors (see below), whose sum is σ = 56954949888. Its totient is φ = 7279614720.

The previous prime is 21333433469. The next prime is 21333433543. The reversal of 21333433520 is 2533433312.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27887 + ... + 208433.

Almost surely, 2^21333433520 is an apocalyptic number.

21333433520 is a gapful number since it is divisible by the number (20) 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 21333433520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28477474944).

21333433520 is an abundant number, since it is smaller than the sum of its proper divisors (35621516368).

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

21333433520 is a wasteful number, since it uses less digits than its factorization.

21333433520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180778 (or 180772 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 29.

Adding to 21333433520 its reverse (2533433312), we get a palindrome (23866866832).

The spelling of 21333433520 in words is "twenty-one billion, three hundred thirty-three million, four hundred thirty-three thousand, five hundred twenty".