23121216 has 84 divisors (see below), whose sum is σ = 66984372. Its totient is φ = 7624704.

The previous prime is 23121209. The next prime is 23121247. The reversal of 23121216 is 61212132.

It can be written as a sum of positive squares in 2 ways, for example, as 18455616 + 4665600 = 4296^2 + 2160^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78766 + ... + 79058.

It is an arithmetic number, because the mean of its divisors is an integer number (797433).

Almost surely, 2^23121216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 23121216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33492186).

23121216 is an abundant number, since it is smaller than the sum of its proper divisors (43863156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

23121216 is a wasteful number, since it uses less digits than its factorization.

23121216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448 (or 435 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 23121216 is about 4808.4525577362. The cubic root of 23121216 is about 284.8854202385.

Adding to 23121216 its reverse (61212132), we get a palindrome (84333348).

The spelling of 23121216 in words is "twenty-three million, one hundred twenty-one thousand, two hundred sixteen".