21142111 has 4 divisors (see below), whose sum is σ = 21633832. Its totient is φ = 20650392.

The previous prime is 21142109. The next prime is 21142123. The reversal of 21142111 is 11124112.

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 21142111 - 2¹ = 21142109 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21142091 and 21142100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245796 + ... + 245881.

It is an arithmetic number, because the mean of its divisors is an integer number (5408458).

Almost surely, 2^21142111 is an apocalyptic number.

21142111 is a deficient number, since it is larger than the sum of its proper divisors (491721).

21142111 is an equidigital number, since it uses as much as digits as its factorization.

21142111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491720.

The product of its digits is 16, while the sum is 13.

The square root of 21142111 is about 4598.0551323358. The cubic root of 21142111 is about 276.5133579107.

Adding to 21142111 its reverse (11124112), we get a palindrome (32266223).

It can be divided in two parts, 2114 and 2111, that added together give a square (4225 = 65²).

The spelling of 21142111 in words is "twenty-one million, one hundred forty-two thousand, one hundred eleven".