21212122222 has 8 divisors (see below), whose sum is σ = 31818801672. Its totient is φ = 10605855000.

The previous prime is 21212122219. The next prime is 21212122229. The reversal of 21212122222 is 22222121212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21212122222² (a number of 21 digits) contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21212122222.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212122229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145072 + ... + 251932.

It is an arithmetic number, because the mean of its divisors is an integer number (3977350209).

Almost surely, 2^21212122222 is an apocalyptic number.

21212122222 is a deficient number, since it is larger than the sum of its proper divisors (10606679450).

21212122222 is a wasteful number, since it uses less digits than its factorization.

21212122222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206114.

The product of its digits is 256, while the sum is 19.

Adding to 21212122222 its reverse (22222121212), we get a palindrome (43434243434).

The spelling of 21212122222 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-two".