21011001122111 has 16 divisors (see below), whose sum is σ = 28210574934528. Its totient is φ = 15112807999200.

The previous prime is 21011001122101. The next prime is 21011001122113. The reversal of 21011001122111 is 11122110011012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011001122111 is a prime.

It is a super-2 number, since 2×21011001122111² (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 (21011001122113) 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, 10495004555 + ... + 10495006556.

It is an arithmetic number, because the mean of its divisors is an integer number (1763160933408).

Almost surely, 2^{21011001122111} is an apocalyptic number.

21011001122111 is a deficient number, since it is larger than the sum of its proper divisors (7199573812417).

21011001122111 is a wasteful number, since it uses less digits than its factorization.

21011001122111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20990011142.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21011001122111 its reverse (11122110011012), we get a palindrome (32133111133123).

It can be divided in two parts, 21011001 and 122111, that added together give a palindrome (21133112).

The spelling of 21011001122111 in words is "twenty-one trillion, eleven billion, one million, one hundred twenty-two thousand, one hundred eleven".