21111123 has 8 divisors (see below), whose sum is σ = 30707136. Its totient is φ = 12794600.

The previous prime is 21111113. The next prime is 21111143. The reversal of 21111123 is 32111112.

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 21111123 - 2⁸ = 21110867 is a prime.

It is a super-2 number, since 2×21111123² = 891359028642258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21111099 and 21111108.

It is not an unprimeable number, because it can be changed into a prime (21111113) 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, 319833 + ... + 319898.

It is an arithmetic number, because the mean of its divisors is an integer number (3838392).

Almost surely, 2^21111123 is an apocalyptic number.

21111123 is a deficient number, since it is larger than the sum of its proper divisors (9596013).

21111123 is a wasteful number, since it uses less digits than its factorization.

21111123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639745.

The product of its digits is 12, while the sum is 12.

The square root of 21111123 is about 4594.6842111292. The cubic root of 21111123 is about 276.3781966098.

Adding to 21111123 its reverse (32111112), we get a palindrome (53222235).

It can be divided in two parts, 2111112 and 3, that multiplied together give a palindrome (6333336).

The spelling of 21111123 in words is "twenty-one million, one hundred eleven thousand, one hundred twenty-three".