12217128 has 96 divisors (see below), whose sum is σ = 38431680. Its totient is φ = 3168000.

The previous prime is 12217109. The next prime is 12217147. The reversal of 12217128 is 82171221.

12217128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (12217109) and next prime (12217147).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 12217098 and 12217107.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20028 + ... + 20628.

It is an arithmetic number, because the mean of its divisors is an integer number (400330).

Almost surely, 2^12217128 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 12217128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19215840).

12217128 is an abundant number, since it is smaller than the sum of its proper divisors (26214552).

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

12217128 is a wasteful number, since it uses less digits than its factorization.

12217128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639 (or 624 counting only the distinct ones).

The product of its digits is 448, while the sum is 24.

The square root of 12217128 is about 3495.3008454209. The cubic root of 12217128 is about 230.3154336153.

Adding to 12217128 its reverse (82171221), we get a palindrome (94388349).

The spelling of 12217128 in words is "twelve million, two hundred seventeen thousand, one hundred twenty-eight".