21212030 has 16 divisors (see below), whose sum is σ = 43636320. Its totient is φ = 7272672.

The previous prime is 21212017. The next prime is 21212033. The reversal of 21212030 is 3021212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212033) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151445 + ... + 151584.

It is an arithmetic number, because the mean of its divisors is an integer number (2727270).

Almost surely, 2^21212030 is an apocalyptic number.

21212030 is an abundant number, since it is smaller than the sum of its proper divisors (22424290).

21212030 is a wasteful number, since it uses less digits than its factorization.

21212030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303043.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21212030 is about 4605.6519625347. The cubic root of 21212030 is about 276.8178412854.

Adding to 21212030 its reverse (3021212), we get a palindrome (24233242).

The spelling of 21212030 in words is "twenty-one million, two hundred twelve thousand, thirty".