12215728 has 40 divisors (see below), whose sum is σ = 27989280. Its totient is φ = 5053440.

The previous prime is 12215713. The next prime is 12215743. The reversal of 12215728 is 82751221.

12215728 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 (12215713) and next prime (12215743).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 12215696 and 12215705.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1368 + ... + 5128.

It is an arithmetic number, because the mean of its divisors is an integer number (699732).

Almost surely, 2^12215728 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 12215728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13994640).

12215728 is an abundant number, since it is smaller than the sum of its proper divisors (15773552).

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

12215728 is a wasteful number, since it uses less digits than its factorization.

12215728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3805 (or 3799 counting only the distinct ones).

The product of its digits is 2240, while the sum is 28.

The square root of 12215728 is about 3495.1005707991. The cubic root of 12215728 is about 230.3066357504.

Adding to 12215728 its reverse (82751221), we get a palindrome (94966949).

The spelling of 12215728 in words is "twelve million, two hundred fifteen thousand, seven hundred twenty-eight".