21221121212 has 12 divisors (see below), whose sum is σ = 38751612816. Its totient is φ = 10149231840.

The previous prime is 21221121167. The next prime is 21221121241. The reversal of 21221121212 is 21212112212.

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, 115332089 + ... + 115332272.

It is an arithmetic number, because the mean of its divisors is an integer number (3229301068).

Almost surely, 2^21221121212 is an apocalyptic number.

It is an amenable number.

21221121212 is a deficient number, since it is larger than the sum of its proper divisors (17530491604).

21221121212 is a wasteful number, since it uses less digits than its factorization.

21221121212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230664388 (or 230664386 counting only the distinct ones).

The product of its digits is 64, while the sum is 17.

Adding to 21221121212 its reverse (21212112212), we get a palindrome (42433233424).

The spelling of 21221121212 in words is "twenty-one billion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred twelve".