21221214 has 96 divisors (see below), whose sum is σ = 54172800. Its totient is φ = 5503680.

The previous prime is 21221171. The next prime is 21221237. The reversal of 21221214 is 41212212.

It is a junction number, because it is equal to n+sod(n) for n = 21221193 and 21221202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 161929 + ... + 162059.

It is an arithmetic number, because the mean of its divisors is an integer number (564300).

Almost surely, 2^21221214 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221214, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27086400).

21221214 is an abundant number, since it is smaller than the sum of its proper divisors (32951586).

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

21221214 is a wasteful number, since it uses less digits than its factorization.

21221214 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198 (or 191 counting only the distinct ones).

The product of its digits is 64, while the sum is 15.

The square root of 21221214 is about 4606.6488904626. The cubic root of 21221214 is about 276.8577860438.

Adding to 21221214 its reverse (41212212), we get a palindrome (62433426).

It can be divided in two parts, 212212 and 14, that added together give a triangular number (212226 = T₆₅₁).

The spelling of 21221214 in words is "twenty-one million, two hundred twenty-one thousand, two hundred fourteen".