21221111021212 has 6 divisors (see below), whose sum is σ = 37136944287128. Its totient is φ = 10610555510604.

The previous prime is 21221111021191. The next prime is 21221111021213. The reversal of 21221111021212 is 21212011112212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221111021212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221111021213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2652638877648 + ... + 2652638877655.

Almost surely, 2^{21221111021212} is an apocalyptic number.

It is an amenable number.

21221111021212 is a deficient number, since it is larger than the sum of its proper divisors (15915833265916).

21221111021212 is a wasteful number, since it uses less digits than its factorization.

21221111021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305277755307 (or 5305277755305 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21221111021212 its reverse (21212011112212), we get a palindrome (42433122133424).

The spelling of 21221111021212 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, twenty-one thousand, two hundred twelve".