21121112212 has 12 divisors (see below), whose sum is σ = 37105768980. Its totient is φ = 10519463936.

The previous prime is 21121112209. The next prime is 21121112237. The reversal of 21121112212 is 21221112112.

It can be written as a sum of positive squares in 2 ways, for example, as 16680755716 + 4440356496 = 129154^2 + 66636^2 .

It is a super-2 number, since 2×21121112212² (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 congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 10271887 + ... + 10273942.

It is an arithmetic number, because the mean of its divisors is an integer number (3092147415).

Almost surely, 2^21121112212 is an apocalyptic number.

It is an amenable number.

21121112212 is a deficient number, since it is larger than the sum of its proper divisors (15984656768).

21121112212 is a wasteful number, since it uses less digits than its factorization.

21121112212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20546090 (or 20546088 counting only the distinct ones).

The product of its digits is 32, while the sum is 16.

Adding to 21121112212 its reverse (21221112112), we get a palindrome (42342224324).

The spelling of 21121112212 in words is "twenty-one billion, one hundred twenty-one million, one hundred twelve thousand, two hundred twelve".