21020110111 has 24 divisors (see below), whose sum is σ = 28726793424. Its totient is φ = 15119354880.

The previous prime is 21020110091. The next prime is 21020110121. The reversal of 21020110111 is 11101102012.

It is not a de Polignac number, because 21020110111 - 2¹³ = 21020101919 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020110121) 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, 1492930 + ... + 1506943.

It is an arithmetic number, because the mean of its divisors is an integer number (1196949726).

Almost surely, 2^21020110111 is an apocalyptic number.

21020110111 is a deficient number, since it is larger than the sum of its proper divisors (7706683313).

21020110111 is a wasteful number, since it uses less digits than its factorization.

21020110111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2999911 (or 2999904 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21020110111 its reverse (11101102012), we get a palindrome (32121212123).

It can be divided in two parts, 21020 and 110111, that added together give a palindrome (131131).

The spelling of 21020110111 in words is "twenty-one billion, twenty million, one hundred ten thousand, one hundred eleven".