21212121222111 has 8 divisors (see below), whose sum is σ = 28293923962800. Its totient is φ = 14135866314752.

The previous prime is 21212121222067. The next prime is 21212121222121. The reversal of 21212121222111 is 11122212121212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21212121222111 - 2¹⁰ = 21212121221087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212121222121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1386949410 + ... + 1386964703.

It is an arithmetic number, because the mean of its divisors is an integer number (3536740495350).

Almost surely, 2^{21212121222111} is an apocalyptic number.

21212121222111 is a deficient number, since it is larger than the sum of its proper divisors (7081802740689).

21212121222111 is a wasteful number, since it uses less digits than its factorization.

21212121222111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773916665.

The product of its digits is 128, while the sum is 21.

Adding to 21212121222111 its reverse (11122212121212), we get a palindrome (32334333343323).

The spelling of 21212121222111 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, two hundred twenty-two thousand, one hundred eleven".