21212212 has 12 divisors (see below), whose sum is σ = 42424480. Its totient is φ = 9090936.

The previous prime is 21212197. The next prime is 21212239. The reversal of 21212212 is 21221212.

It is a happy number.

21212212 is an admirable number.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21212192 and 21212201.

It is a congruent 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 3 ways as a sum of consecutive naturals, for example, 378762 + ... + 378817.

Almost surely, 2^21212212 is an apocalyptic number.

It is an amenable number.

21212212 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21212212 is a wasteful number, since it uses less digits than its factorization.

21212212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757590 (or 757588 counting only the distinct ones).

The product of its digits is 32, while the sum is 13.

The square root of 21212212 is about 4605.6717208242. The cubic root of 21212212 is about 276.8186329856.

Adding to 21212212 its reverse (21221212), we get a palindrome (42433424).

It can be divided in two parts, 21212 and 212, that multiplied together give a palindrome (4496944).

The spelling of 21212212 in words is "twenty-one million, two hundred twelve thousand, two hundred twelve".