21123111023 has 8 divisors (see below), whose sum is σ = 24141594240. Its totient is φ = 18104851800.

The previous prime is 21123111011. The next prime is 21123111047. The reversal of 21123111023 is 32011132112.

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

It is not a de Polignac number, because 21123111023 - 2¹⁰ = 21123109999 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21123110992 and 21123111010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123111073) 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, 282548 + ... + 349398.

It is an arithmetic number, because the mean of its divisors is an integer number (3017699280).

Almost surely, 2^21123111023 is an apocalyptic number.

21123111023 is a deficient number, since it is larger than the sum of its proper divisors (3018483217).

21123111023 is an equidigital number, since it uses as much as digits as its factorization.

21123111023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111997.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21123111023 its reverse (32011132112), we get a palindrome (53134243135).

The spelling of 21123111023 in words is "twenty-one billion, one hundred twenty-three million, one hundred eleven thousand, twenty-three".