21212202222 has 12 divisors (see below), whose sum is σ = 45959771520. Its totient is φ = 7070734068.

The previous prime is 21212202173. The next prime is 21212202227. The reversal of 21212202222 is 22220221212.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1178455679 = 21212202222 / (2 + 1 + 2 + 1 + 2 + 2 + 0 + 2 + 2 + 2 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 21212202195 and 21212202204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212202227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 589227822 + ... + 589227857.

It is an arithmetic number, because the mean of its divisors is an integer number (3829980960).

Almost surely, 2^21212202222 is an apocalyptic number.

21212202222 is an abundant number, since it is smaller than the sum of its proper divisors (24747569298).

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

21212202222 is a wasteful number, since it uses less digits than its factorization.

21212202222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178455687 (or 1178455684 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21212202222 its reverse (22220221212), we get a palindrome (43432423434).

The spelling of 21212202222 in words is "twenty-one billion, two hundred twelve million, two hundred two thousand, two hundred twenty-two".