21323011111 has 4 divisors (see below), whose sum is σ = 21324251824. Its totient is φ = 21321770400.

The previous prime is 21323011109. The next prime is 21323011121. The reversal of 21323011111 is 11111032312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21323011111 - 2¹ = 21323011109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323011121) 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, 594210 + ... + 629071.

It is an arithmetic number, because the mean of its divisors is an integer number (5331062956).

Almost surely, 2^21323011111 is an apocalyptic number.

21323011111 is a deficient number, since it is larger than the sum of its proper divisors (1240713).

21323011111 is a wasteful number, since it uses less digits than its factorization.

21323011111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1240712.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 21323011111 its reverse (11111032312), we get a palindrome (32434043423).

The spelling of 21323011111 in words is "twenty-one billion, three hundred twenty-three million, eleven thousand, one hundred eleven".