21212231023 has 4 divisors (see below), whose sum is σ = 21214771600. Its totient is φ = 21209690448.

The previous prime is 21212230909. The next prime is 21212231039. The reversal of 21212231023 is 32013221212.

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-21212231023 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 (21212237023) 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, 1257723 + ... + 1274476.

It is an arithmetic number, because the mean of its divisors is an integer number (5303692900).

Almost surely, 2^21212231023 is an apocalyptic number.

21212231023 is a deficient number, since it is larger than the sum of its proper divisors (2540577).

21212231023 is an equidigital number, since it uses as much as digits as its factorization.

21212231023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2540576.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21212231023 its reverse (32013221212), we get a palindrome (53225452235).

The spelling of 21212231023 in words is "twenty-one billion, two hundred twelve million, two hundred thirty-one thousand, twenty-three".