21212111201212 has 48 divisors (see below), whose sum is σ = 38602205752320. Its totient is φ = 10187987990400.

The previous prime is 21212111201207. The next prime is 21212111201221. The reversal of 21212111201212 is 21210211121212.

It is a happy number.

It is a super-2 number, since 2×21212111201212² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21212111201212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 186454387 + ... + 186568117.

It is an arithmetic number, because the mean of its divisors is an integer number (804212619840).

Almost surely, 2^{21212111201212} is an apocalyptic number.

It is an amenable number.

21212111201212 is a deficient number, since it is larger than the sum of its proper divisors (17390094551108).

21212111201212 is a wasteful number, since it uses less digits than its factorization.

21212111201212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124882 (or 124880 counting only the distinct ones).

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

Adding to 21212111201212 its reverse (21210211121212), we get a palindrome (42422322322424).

The spelling of 21212111201212 in words is "twenty-one trillion, two hundred twelve billion, one hundred eleven million, two hundred one thousand, two hundred twelve".