8720640 has 108 divisors (see below), whose sum is σ = 30212364. Its totient is φ = 2322432.

The previous prime is 8720629. The next prime is 8720671. The reversal of 8720640 is 460278.

It can be written as a sum of positive squares in 2 ways, for example, as 4260096 + 4460544 = 2064^2 + 2112^2 .

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11142 + ... + 11898.

Almost surely, 2^8720640 is an apocalyptic number.

8720640 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 8720640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15106182).

8720640 is an abundant number, since it is smaller than the sum of its proper divisors (21491724).

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

8720640 is a wasteful number, since it uses less digits than its factorization.

8720640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784 (or 767 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 8720640 is about 2953.0729757322. The cubic root of 8720640 is about 205.8335287506.

The spelling of 8720640 in words is "eight million, seven hundred twenty thousand, six hundred forty".