21021110111 has 16 divisors (see below), whose sum is σ = 21407320224. Its totient is φ = 20639207424.

The previous prime is 21021110093. The next prime is 21021110119. The reversal of 21021110111 is 11101112012.

It is a cyclic number.

It is not a de Polignac number, because 21021110111 - 2¹⁴ = 21021093727 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021110092 and 21021110101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021110119) 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, 6532775 + ... + 6535991.

It is an arithmetic number, because the mean of its divisors is an integer number (1337957514).

Almost surely, 2^21021110111 is an apocalyptic number.

21021110111 is a deficient number, since it is larger than the sum of its proper divisors (386210113).

21021110111 is a wasteful number, since it uses less digits than its factorization.

21021110111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3850.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21021110111 its reverse (11101112012), we get a palindrome (32122222123).

The spelling of 21021110111 in words is "twenty-one billion, twenty-one million, one hundred ten thousand, one hundred eleven".