21102021011023 has 4 divisors (see below), whose sum is σ = 21102455320128. Its totient is φ = 21101586701920.

The previous prime is 21102021010981. The next prime is 21102021011069. The reversal of 21102021011023 is 32011012020112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21102021011023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102021010988 and 21102021011006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102021011623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 217081663 + ... + 217178848.

It is an arithmetic number, because the mean of its divisors is an integer number (5275613830032).

Almost surely, 2^{21102021011023} is an apocalyptic number.

21102021011023 is a deficient number, since it is larger than the sum of its proper divisors (434309105).

21102021011023 is an equidigital number, since it uses as much as digits as its factorization.

21102021011023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434309104.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21102021011023 its reverse (32011012020112), we get a palindrome (53113033031135).

The spelling of 21102021011023 in words is "twenty-one trillion, one hundred two billion, twenty-one million, eleven thousand, twenty-three".