21333522 has 48 divisors (see below), whose sum is σ = 50068800. Its totient is φ = 6041952.

The previous prime is 21333511. The next prime is 21333539. The reversal of 21333522 is 22533312.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 43563 + ... + 44049.

It is an arithmetic number, because the mean of its divisors is an integer number (1043100).

Almost surely, 2^21333522 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21333522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25034400).

21333522 is an abundant number, since it is smaller than the sum of its proper divisors (28735278).

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

21333522 is a wasteful number, since it uses less digits than its factorization.

21333522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655 (or 648 counting only the distinct ones).

The product of its digits is 1080, while the sum is 21.

The square root of 21333522 is about 4618.8225772376. The cubic root of 21333522 is about 277.3453273263.

Adding to 21333522 its reverse (22533312), we get a palindrome (43866834).

The spelling of 21333522 in words is "twenty-one million, three hundred thirty-three thousand, five hundred twenty-two".