21120012111 has 16 divisors (see below), whose sum is σ = 31001857920. Its totient is φ = 12682573920.

The previous prime is 21120012107. The next prime is 21120012119. The reversal of 21120012111 is 11121002112.

It is not a de Polignac number, because 21120012111 - 2² = 21120012107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120012119) 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, 2932185 + ... + 2939378.

It is an arithmetic number, because the mean of its divisors is an integer number (1937616120).

Almost surely, 2^21120012111 is an apocalyptic number.

21120012111 is a deficient number, since it is larger than the sum of its proper divisors (9881845809).

21120012111 is a wasteful number, since it uses less digits than its factorization.

21120012111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5871686.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21120012111 its reverse (11121002112), we get a palindrome (32241014223).

Subtracting from 21120012111 its reverse (11121002112), we obtain a palindrome (9999009999).

It can be divided in two parts, 2112001 and 2111, that added together give a palindrome (2114112).

The spelling of 21120012111 in words is "twenty-one billion, one hundred twenty million, twelve thousand, one hundred eleven".