21222012 has 48 divisors (see below), whose sum is σ = 59575040. Its totient is φ = 5743872.

The previous prime is 21221953. The next prime is 21222013. The reversal of 21222012 is 21022212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5053 + ... + 8244.

Almost surely, 2^21222012 is an apocalyptic number.

It is an amenable number.

21222012 is an abundant number, since it is smaller than the sum of its proper divisors (38353028).

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

21222012 is a wasteful number, since it uses less digits than its factorization.

21222012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13330 (or 13328 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21222012 is about 4606.7355035860. The cubic root of 21222012 is about 276.8612563093.

Adding to 21222012 its reverse (21022212), we get a palindrome (42244224).

The spelling of 21222012 in words is "twenty-one million, two hundred twenty-two thousand, twelve".