21113212 has 6 divisors (see below), whose sum is σ = 36948128. Its totient is φ = 10556604.

The previous prime is 21113173. The next prime is 21113221. The reversal of 21113212 is 21231112.

It is a junction number, because it is equal to n+sod(n) for n = 21113192 and 21113201.

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 as a sum of consecutive naturals, namely, 2639148 + ... + 2639155.

Almost surely, 2^21113212 is an apocalyptic number.

It is an amenable number.

21113212 is a deficient number, since it is larger than the sum of its proper divisors (15834916).

21113212 is a wasteful number, since it uses less digits than its factorization.

21113212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5278307 (or 5278305 counting only the distinct ones).

The product of its digits is 24, while the sum is 13.

The square root of 21113212 is about 4594.9115334248. The cubic root of 21113212 is about 276.3873124206.

Adding to 21113212 its reverse (21231112), we get a palindrome (42344324).

The spelling of 21113212 in words is "twenty-one million, one hundred thirteen thousand, two hundred twelve".