21122111111 has 24 divisors (see below), whose sum is σ = 22877337600. Its totient is φ = 19463828384.

The previous prime is 21122111107. The next prime is 21122111117. The reversal of 21122111111 is 11111122112.

It is not a de Polignac number, because 21122111111 - 2² = 21122111107 is a prime.

It is a super-2 number, since 2×21122111111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

21122111111 is a modest number, since divided by 111111 gives 21122 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122111117) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11585546 + ... + 11587368.

It is an arithmetic number, because the mean of its divisors is an integer number (953222400).

Almost surely, 2^21122111111 is an apocalyptic number.

21122111111 is a deficient number, since it is larger than the sum of its proper divisors (1755226489).

21122111111 is a wasteful number, since it uses less digits than its factorization.

21122111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2503 (or 2474 counting only the distinct ones).

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

Adding to 21122111111 its reverse (11111122112), we get a palindrome (32233233223).

The spelling of 21122111111 in words is "twenty-one billion, one hundred twenty-two million, one hundred eleven thousand, one hundred eleven".