21211221212 has 6 divisors (see below), whose sum is σ = 37119637128. Its totient is φ = 10605610604.

The previous prime is 21211221179. The next prime is 21211221223. The reversal of 21211221212 is 21212211212.

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 polite number, since it can be written as a sum of consecutive naturals, namely, 2651402648 + ... + 2651402655.

It is an arithmetic number, because the mean of its divisors is an integer number (6186606188).

Almost surely, 2^21211221212 is an apocalyptic number.

It is an amenable number.

21211221212 is a deficient number, since it is larger than the sum of its proper divisors (15908415916).

21211221212 is a wasteful number, since it uses less digits than its factorization.

21211221212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5302805307 (or 5302805305 counting only the distinct ones).

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

Adding to 21211221212 its reverse (21212211212), we get a palindrome (42423432424).

The spelling of 21211221212 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred twelve".