8720864 has 72 divisors (see below), whose sum is σ = 19495728. Its totient is φ = 3829760.

The previous prime is 8720839. The next prime is 8720891. The reversal of 8720864 is 4680278.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 212684 + ... + 212724.

It is an arithmetic number, because the mean of its divisors is an integer number (270774).

Almost surely, 2^8720864 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 8720864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9747864).

8720864 is an abundant number, since it is smaller than the sum of its proper divisors (10774864).

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

8720864 is a wasteful number, since it uses less digits than its factorization.

8720864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 35.

The square root of 8720864 is about 2953.1109020828. The cubic root of 8720864 is about 205.8352910951.

The spelling of 8720864 in words is "eight million, seven hundred twenty thousand, eight hundred sixty-four".