21221020111111 has 16 divisors (see below), whose sum is σ = 21528028222848. Its totient is φ = 20915933428000.

The previous prime is 21221020111043. The next prime is 21221020111139. The reversal of 21221020111111 is 11111102012212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221020111111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221020115111) by changing a digit.

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, 217551396 + ... + 217648918.

It is an arithmetic number, because the mean of its divisors is an integer number (1345501763928).

Almost surely, 2^{21221020111111} is an apocalyptic number.

21221020111111 is a deficient number, since it is larger than the sum of its proper divisors (307008111737).

21221020111111 is a wasteful number, since it uses less digits than its factorization.

21221020111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107342.

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

Adding to 21221020111111 its reverse (11111102012212), we get a palindrome (32332122123323).

The spelling of 21221020111111 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, one hundred eleven thousand, one hundred eleven".