21113123111 has 8 divisors (see below), whose sum is σ = 21352937760. Its totient is φ = 20873760768.

The previous prime is 21113123107. The next prime is 21113123177. The reversal of 21113123111 is 11132131112.

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 21113123111 - 2² = 21113123107 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21113123111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113123011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18746 + ... + 206343.

It is an arithmetic number, because the mean of its divisors is an integer number (2669117220).

Almost surely, 2^21113123111 is an apocalyptic number.

21113123111 is a deficient number, since it is larger than the sum of its proper divisors (239814649).

21113123111 is an equidigital number, since it uses as much as digits as its factorization.

21113123111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226153.

The product of its digits is 36, while the sum is 17.

Adding to 21113123111 its reverse (11132131112), we get a palindrome (32245254223).

The spelling of 21113123111 in words is "twenty-one billion, one hundred thirteen million, one hundred twenty-three thousand, one hundred eleven".