21221020011111 has 16 divisors (see below), whose sum is σ = 28367067348480. Its totient is φ = 14111205688800.

The previous prime is 21221020011091. The next prime is 21221020011137. The reversal of 21221020011111 is 11111002012212.

It is a happy number.

It is not a de Polignac number, because 21221020011111 - 2⁶ = 21221020011047 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221020011181) 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, 3906115 + ... + 7596036.

It is an arithmetic number, because the mean of its divisors is an integer number (1772941709280).

Almost surely, 2^{21221020011111} is an apocalyptic number.

21221020011111 is a deficient number, since it is larger than the sum of its proper divisors (7146047337369).

21221020011111 is a wasteful number, since it uses less digits than its factorization.

21221020011111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11503726.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21221020011111 its reverse (11111002012212), we get a palindrome (32332022023323).

The spelling of 21221020011111 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, eleven thousand, one hundred eleven".