21011112111 has 8 divisors (see below), whose sum is σ = 30561617664. Its totient is φ = 12734007320.

The previous prime is 21011112097. The next prime is 21011112131. The reversal of 21011112111 is 11121111012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011112111 - 2⁶ = 21011112047 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011112131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 318350151 + ... + 318350216.

It is an arithmetic number, because the mean of its divisors is an integer number (3820202208).

Almost surely, 2^21011112111 is an apocalyptic number.

21011112111 is a deficient number, since it is larger than the sum of its proper divisors (9550505553).

21011112111 is a wasteful number, since it uses less digits than its factorization.

21011112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636700381.

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

Adding to 21011112111 its reverse (11121111012), we get a palindrome (32132223123).

It can be divided in two parts, 210111 and 12111, that added together give a palindrome (222222).

The spelling of 21011112111 in words is "twenty-one billion, eleven million, one hundred twelve thousand, one hundred eleven".