8217920 has 56 divisors (see below), whose sum is σ = 19936968. Its totient is φ = 3225600.

The previous prime is 8217893. The next prime is 8217929. The reversal of 8217920 is 297128.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 906304 + 7311616 = 952^2 + 2704^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8217929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19310 + ... + 19730.

Almost surely, 2^8217920 is an apocalyptic number.

8217920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8217920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9968484).

8217920 is an abundant number, since it is smaller than the sum of its proper divisors (11719048).

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

8217920 is a wasteful number, since it uses less digits than its factorization.

8217920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499 (or 489 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 8217920 is about 2866.6914727609. The cubic root of 8217920 is about 201.7997558148.

The spelling of 8217920 in words is "eight million, two hundred seventeen thousand, nine hundred twenty".