21304212 has 36 divisors (see below), whose sum is σ = 51507456. Its totient is φ = 6853280.

The previous prime is 21304147. The next prime is 21304219. The reversal of 21304212 is 21240312.

It is a junction number, because it is equal to n+sod(n) for n = 21304191 and 21304200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304219) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9037 + ... + 11147.

Almost surely, 2^21304212 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 21304212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25753728).

21304212 is an abundant number, since it is smaller than the sum of its proper divisors (30203244).

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

21304212 is a wasteful number, since it uses less digits than its factorization.

21304212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2176 (or 2145 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21304212 is about 4615.6486001428. The cubic root of 21304212 is about 277.2182547442.

Adding to 21304212 its reverse (21240312), we get a palindrome (42544524).

The spelling of 21304212 in words is "twenty-one million, three hundred four thousand, two hundred twelve".