21111021221212 has 48 divisors (see below), whose sum is σ = 39808260761472. Its totient is φ = 9738136175040.

The previous prime is 21111021221123. The next prime is 21111021221233. The reversal of 21111021221212 is 21212212011112.

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 21111021221212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1000179963 + ... + 1000201069.

It is an arithmetic number, because the mean of its divisors is an integer number (829338765864).

Almost surely, 2^{21111021221212} is an apocalyptic number.

It is an amenable number.

21111021221212 is a deficient number, since it is larger than the sum of its proper divisors (18697239540260).

21111021221212 is a wasteful number, since it uses less digits than its factorization.

21111021221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30898 (or 30896 counting only the distinct ones).

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

Adding to 21111021221212 its reverse (21212212011112), we get a palindrome (42323233232324).

The spelling of 21111021221212 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, two hundred twenty-one thousand, two hundred twelve".