8640840 has 128 divisors (see below), whose sum is σ = 29030400. Its totient is φ = 2042880.

The previous prime is 8640823. The next prime is 8640859. The reversal of 8640840 is 480468.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 8640798 and 8640807.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45145 + ... + 45335.

It is an arithmetic number, because the mean of its divisors is an integer number (226800).

Almost surely, 2^8640840 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 8640840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14515200).

8640840 is an abundant number, since it is smaller than the sum of its proper divisors (20389560).

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

8640840 is a wasteful number, since it uses less digits than its factorization.

8640840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247 (or 243 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 8640840 is about 2939.5305747687. The cubic root of 8640840 is about 205.2037632922.

The spelling of 8640840 in words is "eight million, six hundred forty thousand, eight hundred forty".