21303522 has 48 divisors (see below), whose sum is σ = 49008960. Its totient is φ = 6669216.

The previous prime is 21303511. The next prime is 21303523. The reversal of 21303522 is 22530312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21303495 and 21303504.

It is not an unprimeable number, because it can be changed into a prime (21303523) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56928 + ... + 57300.

It is an arithmetic number, because the mean of its divisors is an integer number (1021020).

Almost surely, 2^21303522 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21303522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24504480).

21303522 is an abundant number, since it is smaller than the sum of its proper divisors (27705438).

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

21303522 is a wasteful number, since it uses less digits than its factorization.

21303522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 567 (or 564 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21303522 is about 4615.5738538128. The cubic root of 21303522 is about 277.2152618672.

Adding to 21303522 its reverse (22530312), we get a palindrome (43833834).

The spelling of 21303522 in words is "twenty-one million, three hundred three thousand, five hundred twenty-two".