21101113111 has 4 divisors (see below), whose sum is σ = 22724275672. Its totient is φ = 19477950552.

The previous prime is 21101113109. The next prime is 21101113127. The reversal of 21101113111 is 11131110112.

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

It is a cyclic number.

It is not a de Polignac number, because 21101113111 - 2¹ = 21101113109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1623162547 = 21101113111 / (2 + 1 + 1 + 0 + 1 + 1 + 1 + 3 + 1 + 1 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101113091 and 21101113100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101111111) 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, 811581261 + ... + 811581286.

It is an arithmetic number, because the mean of its divisors is an integer number (5681068918).

Almost surely, 2^21101113111 is an apocalyptic number.

21101113111 is a deficient number, since it is larger than the sum of its proper divisors (1623162561).

21101113111 is a wasteful number, since it uses less digits than its factorization.

21101113111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623162560.

The product of its (nonzero) digits is 6, while the sum is 13.

Adding to 21101113111 its reverse (11131110112), we get a palindrome (32232223223).

The spelling of 21101113111 in words is "twenty-one billion, one hundred one million, one hundred thirteen thousand, one hundred eleven".