21123111113 has 32 divisors (see below), whose sum is σ = 23241926400. Its totient is φ = 19081370880.

The previous prime is 21123111109. The next prime is 21123111127. The reversal of 21123111113 is 31111132112.

It is not a de Polignac number, because 21123111113 - 2² = 21123111109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123111091 and 21123111100.

It is not an unprimeable number, because it can be changed into a prime (21123111313) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 53206631 + ... + 53207027.

It is an arithmetic number, because the mean of its divisors is an integer number (726310200).

Almost surely, 2^21123111113 is an apocalyptic number.

It is an amenable number.

21123111113 is a deficient number, since it is larger than the sum of its proper divisors (2118815287).

21123111113 is a wasteful number, since it uses less digits than its factorization.

21123111113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897.

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

Adding to 21123111113 its reverse (31111132112), we get a palindrome (52234243225).

The spelling of 21123111113 in words is "twenty-one billion, one hundred twenty-three million, one hundred eleven thousand, one hundred thirteen".