8721216 has 168 divisors, whose sum is σ = 30114240. Its totient is φ = 2467584.

The previous prime is 8721197. The next prime is 8721239. The reversal of 8721216 is 6121278.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (27).

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 an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 8721216.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 84621 + ... + 84723.

Almost surely, 2^8721216 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 8721216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15057120).

8721216 is an abundant number, since it is smaller than the sum of its proper divisors (21393024).

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

8721216 is a wasteful number, since it uses less digits than its factorization.

8721216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 115 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 8721216 is about 2953.1704996495. The cubic root of 8721216 is about 205.8380604326.

The spelling of 8721216 in words is "eight million, seven hundred twenty-one thousand, two hundred sixteen".