21222221222212 has 24 divisors (see below), whose sum is σ = 37865998690520. Its totient is φ = 10405371663360.

The previous prime is 21222221222207. The next prime is 21222221222221. The reversal of 21222221222212 is 21222212222212.

It can be written as a sum of positive squares in 4 ways, for example, as 1496844583936 + 19725376638276 = 1223456^2 + 4441326^2 .

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

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, 250858839 + ... + 250943422.

Almost surely, 2^{21222221222212} is an apocalyptic number.

It is an amenable number.

21222221222212 is a deficient number, since it is larger than the sum of its proper divisors (16643777468308).

21222221222212 is a wasteful number, since it uses less digits than its factorization.

21222221222212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501802471 (or 501802469 counting only the distinct ones).

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

Adding to 21222221222212 its reverse (21222212222212), we get a palindrome (42444433444424).

Subtracting from 21222221222212 its reverse (21222212222212), we obtain a square (9000000 = 3000²).

The spelling of 21222221222212 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twelve".