21121221222 has 12 divisors (see below), whose sum is σ = 45762646020. Its totient is φ = 7040407068.

The previous prime is 21121221221. The next prime is 21121221223. The reversal of 21121221222 is 22212212112.

It is a happy number.

21121221222 is a `hidden beast` number, since 211 + 212 + 21 + 222 = 666.

It is an interprime number because it is at equal distance from previous prime (21121221221) and next prime (21121221223).

It is a super-2 number, since 2×21121221222² (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), and also a Moran number because the ratio is a prime number: 1173401179 = 21121221222 / (2 + 1 + 1 + 2 + 1 + 2 + 2 + 1 + 2 + 2 + 2).

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 = 21121221195 and 21121221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121221221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 586700572 + ... + 586700607.

It is an arithmetic number, because the mean of its divisors is an integer number (3813553835).

Almost surely, 2^21121221222 is an apocalyptic number.

21121221222 is an abundant number, since it is smaller than the sum of its proper divisors (24641424798).

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

21121221222 is a wasteful number, since it uses less digits than its factorization.

21121221222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173401187 (or 1173401184 counting only the distinct ones).

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

Adding to 21121221222 its reverse (22212212112), we get a palindrome (43333433334).

The spelling of 21121221222 in words is "twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, two hundred twenty-two".