23121311221 has 4 divisors (see below), whose sum is σ = 23139333792. Its totient is φ = 23103288652.

The previous prime is 23121311209. The next prime is 23121311237. The reversal of 23121311221 is 12211312132.

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 23121311221 - 2¹⁹ = 23120786933 is a prime.

It is a super-3 number, since 3×23121311221³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23121311251) 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, 9009361 + ... + 9011926.

It is an arithmetic number, because the mean of its divisors is an integer number (5784833448).

Almost surely, 2^23121311221 is an apocalyptic number.

It is an amenable number.

23121311221 is a deficient number, since it is larger than the sum of its proper divisors (18022571).

23121311221 is a wasteful number, since it uses less digits than its factorization.

23121311221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18022570.

The product of its digits is 144, while the sum is 19.

Adding to 23121311221 its reverse (12211312132), we get a palindrome (35332623353).

The spelling of 23121311221 in words is "twenty-three billion, one hundred twenty-one million, three hundred eleven thousand, two hundred twenty-one".