21221221222222 has 16 divisors (see below), whose sum is σ = 36379711255680. Its totient is φ = 9094690376568.

The previous prime is 21221221222217. The next prime is 21221221222241. The reversal of 21221221222222 is 22222212212212.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8778072 + ... + 10931467.

It is an arithmetic number, because the mean of its divisors is an integer number (2273731953480).

Almost surely, 2^{21221221222222} is an apocalyptic number.

21221221222222 is a deficient number, since it is larger than the sum of its proper divisors (15158490033458).

21221221222222 is a wasteful number, since it uses less digits than its factorization.

21221221222222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19786455.

The product of its digits is 2048, while the sum is 25.

Adding to 21221221222222 its reverse (22222212212212), we get a palindrome (43443433434434).

The spelling of 21221221222222 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty-two".