21220120111 has 4 divisors (see below), whose sum is σ = 21225703752. Its totient is φ = 21214536472.

The previous prime is 21220120087. The next prime is 21220120123. The reversal of 21220120111 is 11102102212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21220120111 - 2⁵ = 21220120079 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220120091 and 21220120100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220120711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2786116 + ... + 2793721.

It is an arithmetic number, because the mean of its divisors is an integer number (5306425938).

Almost surely, 2^21220120111 is an apocalyptic number.

21220120111 is a deficient number, since it is larger than the sum of its proper divisors (5583641).

21220120111 is an equidigital number, since it uses as much as digits as its factorization.

21220120111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5583640.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21220120111 its reverse (11102102212), we get a palindrome (32322222323).

The spelling of 21220120111 in words is "twenty-one billion, two hundred twenty million, one hundred twenty thousand, one hundred eleven".