21122121222 has 32 divisors (see below), whose sum is σ = 46961791200. Its totient is φ = 7037145504.

The previous prime is 21122121221. The next prime is 21122121233. The reversal of 21122121222 is 22212122112.

It is a happy number.

21122121222 is a `hidden beast` number, since 211 + 221 + 212 + 22 = 666.

It is a super-2 number, since 2×21122121222² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

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

It is a junction number, because it is equal to n+sod(n) for n = 21122121195 and 21122121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122121221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9904 + ... + 205772.

It is an arithmetic number, because the mean of its divisors is an integer number (1467555975).

Almost surely, 2^21122121222 is an apocalyptic number.

21122121222 is an abundant number, since it is smaller than the sum of its proper divisors (25839669978).

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

21122121222 is a wasteful number, since it uses less digits than its factorization.

21122121222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197877 (or 197871 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

Adding to 21122121222 its reverse (22212122112), we get a palindrome (43334243334).

The spelling of 21122121222 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty-two".