21221201111 has 16 divisors (see below), whose sum is σ = 23722530048. Its totient is φ = 18815524800.

The previous prime is 21221201087. The next prime is 21221201117. The reversal of 21221201111 is 11110212212.

It is a cyclic number.

It is not a de Polignac number, because 21221201111 - 2⁶ = 21221201047 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 (21221201117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2061800 + ... + 2072066.

It is an arithmetic number, because the mean of its divisors is an integer number (1482658128).

Almost surely, 2^21221201111 is an apocalyptic number.

21221201111 is a deficient number, since it is larger than the sum of its proper divisors (2501328937).

21221201111 is a wasteful number, since it uses less digits than its factorization.

21221201111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14902.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21221201111 its reverse (11110212212), we get a palindrome (32331413323).

The spelling of 21221201111 in words is "twenty-one billion, two hundred twenty-one million, two hundred one thousand, one hundred eleven".