21023111121 has 4 divisors (see below), whose sum is σ = 28030814832. Its totient is φ = 14015407412.

The previous prime is 21023111117. The next prime is 21023111129. The reversal of 21023111121 is 12111132012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21023111121 - 2² = 21023111117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21023111121.

It is not an unprimeable number, because it can be changed into a prime (21023111129) 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, 3503851851 + ... + 3503851856.

It is an arithmetic number, because the mean of its divisors is an integer number (7007703708).

Almost surely, 2^21023111121 is an apocalyptic number.

It is an amenable number.

21023111121 is a deficient number, since it is larger than the sum of its proper divisors (7007703711).

21023111121 is an equidigital number, since it uses as much as digits as its factorization.

21023111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7007703710.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21023111121 its reverse (12111132012), we get a palindrome (33134243133).

The spelling of 21023111121 in words is "twenty-one billion, twenty-three million, one hundred eleven thousand, one hundred twenty-one".