23121 has 12 divisors (see below), whose sum is σ = 38272. Its totient is φ = 13176.

The previous prime is 23117. The next prime is 23131. The reversal of 23121 is 12132.

It is a happy number.

It is not a de Polignac number, because 23121 - 2² = 23117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 121 + ... + 246.

2²³¹²¹ is an apocalyptic number.

23121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

23121 is a deficient number, since it is larger than the sum of its proper divisors (15151).

23121 is a wasteful number, since it uses less digits than its factorization.

23121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380 (or 377 counting only the distinct ones).

The product of its digits is 12, while the sum is 9.

The square root of 23121 is about 152.0559107697. The cubic root of 23121 is about 28.4884533096.

Adding to 23121 its reverse (12132), we get a palindrome (35253).

It can be divided in two parts, 231 and 21, that multiplied together give a triangular number (4851 = T₉₈).

The spelling of 23121 in words is "twenty-three thousand, one hundred twenty-one", and thus it is an iban number.