21216230 has 16 divisors (see below), whose sum is σ = 43644960. Its totient is φ = 7274112.

The previous prime is 21216203. The next prime is 21216241. The reversal of 21216230 is 3261212.

It is a junction number, because it is equal to n+sod(n) for n = 21216199 and 21216208.

It is a congruent number.

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, 151475 + ... + 151614.

It is an arithmetic number, because the mean of its divisors is an integer number (2727810).

Almost surely, 2^21216230 is an apocalyptic number.

21216230 is an abundant number, since it is smaller than the sum of its proper divisors (22428730).

21216230 is a wasteful number, since it uses less digits than its factorization.

21216230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303103.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21216230 is about 4606.1079014717. The cubic root of 21216230 is about 276.8361101358.

Adding to 21216230 its reverse (3261212), we get a palindrome (24477442).

The spelling of 21216230 in words is "twenty-one million, two hundred sixteen thousand, two hundred thirty".