28217712 has 40 divisors (see below), whose sum is σ = 73903504. Its totient is φ = 9275904.

The previous prime is 28217701. The next prime is 28217723. The reversal of 28217712 is 21771282.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28217701) and next prime (28217723).

It is a self number, because there is not a number n which added to its sum of digits gives 28217712.

It is a congruent number.

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, 523 + ... + 7530.

Almost surely, 2^28217712 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 28217712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36951752).

28217712 is an abundant number, since it is smaller than the sum of its proper divisors (45685792).

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

28217712 is a wasteful number, since it uses less digits than its factorization.

28217712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8137 (or 8131 counting only the distinct ones).

The product of its digits is 3136, while the sum is 30.

The square root of 28217712 is about 5312.0346384413. The cubic root of 28217712 is about 304.4438921537.

Adding to 28217712 its reverse (21771282), we get a palindrome (49988994).

The spelling of 28217712 in words is "twenty-eight million, two hundred seventeen thousand, seven hundred twelve".