21212300 has 18 divisors (see below), whose sum is σ = 46030908. Its totient is φ = 8484880.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212300 is 321212.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105962 + ... + 106161.

Almost surely, 2^21212300 is an apocalyptic number.

21212300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212300 is an abundant number, since it is smaller than the sum of its proper divisors (24818608).

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

21212300 is a wasteful number, since it uses less digits than its factorization.

21212300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212137 (or 212130 counting only the distinct ones).

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

The square root of 21212300 is about 4605.6812742525. The cubic root of 21212300 is about 276.8190157841.

Adding to 21212300 its reverse (321212), we get a palindrome (21533512).

It can be divided in two parts, 21212 and 300, that added together give a palindrome (21512).

The spelling of 21212300 in words is "twenty-one million, two hundred twelve thousand, three hundred".