21001122021111 has 16 divisors (see below), whose sum is σ = 28399369666560. Its totient is φ = 13802353999200.

The previous prime is 21001122021109. The next prime is 21001122021127. The reversal of 21001122021111 is 11112022110012.

It is a happy number.

It is not a de Polignac number, because 21001122021111 - 2¹ = 21001122021109 is a prime.

It is a super-2 number, since 2×21001122021111² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001122020111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67695415 + ... + 68004936.

It is an arithmetic number, because the mean of its divisors is an integer number (1774960604160).

Almost surely, 2^{21001122021111} is an apocalyptic number.

21001122021111 is a deficient number, since it is larger than the sum of its proper divisors (7398247645449).

21001122021111 is a wasteful number, since it uses less digits than its factorization.

21001122021111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135701086.

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

Adding to 21001122021111 its reverse (11112022110012), we get a palindrome (32113144131123).

The spelling of 21001122021111 in words is "twenty-one trillion, one billion, one hundred twenty-two million, twenty-one thousand, one hundred eleven".