21303212 has 24 divisors (see below), whose sum is σ = 42989856. Its totient is φ = 9047808.

The previous prime is 21303209. The next prime is 21303229. The reversal of 21303212 is 21230312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 203 + ... + 6530.

It is an arithmetic number, because the mean of its divisors is an integer number (1791244).

Almost surely, 2^21303212 is an apocalyptic number.

It is an amenable number.

21303212 is an abundant number, since it is smaller than the sum of its proper divisors (21686644).

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

21303212 is a wasteful number, since it uses less digits than its factorization.

21303212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6857 (or 6855 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21303212 is about 4615.5402717342. The cubic root of 21303212 is about 277.2139172202.

Adding to 21303212 its reverse (21230312), we get a palindrome (42533524).

Subtracting from 21303212 its reverse (21230312), we obtain a square (72900 = 270²).

The spelling of 21303212 in words is "twenty-one million, three hundred three thousand, two hundred twelve".