21112101111 has 4 divisors (see below), whose sum is σ = 28149468152. Its totient is φ = 14074734072.

The previous prime is 21112101103. The next prime is 21112101133. The reversal of 21112101111 is 11110121112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21112101111 - 2³ = 21112101103 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 (21112101911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3518683516 + ... + 3518683521.

It is an arithmetic number, because the mean of its divisors is an integer number (7037367038).

Almost surely, 2^21112101111 is an apocalyptic number.

21112101111 is a deficient number, since it is larger than the sum of its proper divisors (7037367041).

21112101111 is an equidigital number, since it uses as much as digits as its factorization.

21112101111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7037367040.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21112101111 its reverse (11110121112), we get a palindrome (32222222223).

The spelling of 21112101111 in words is "twenty-one billion, one hundred twelve million, one hundred one thousand, one hundred eleven".