21221111111212 has 12 divisors (see below), whose sum is σ = 37136984043096. Its totient is φ = 10610544241760.

The previous prime is 21221111111177. The next prime is 21221111111231. The reversal of 21221111111212 is 21211111112212.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21221111111212.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2512323 + ... + 6982405.

It is an arithmetic number, because the mean of its divisors is an integer number (3094748670258).

Almost surely, 2^{21221111111212} is an apocalyptic number.

It is an amenable number.

21221111111212 is a deficient number, since it is larger than the sum of its proper divisors (15915872931884).

21221111111212 is a wasteful number, since it uses less digits than its factorization.

21221111111212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5656928 (or 5656926 counting only the distinct ones).

The product of its digits is 32, while the sum is 19.

Adding to 21221111111212 its reverse (21211111112212), we get a palindrome (42432222223424).

It can be divided in two parts, 2122111 and 1111212, that added together give a palindrome (3233323).

The spelling of 21221111111212 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred eleven thousand, two hundred twelve".