8640438 has 16 divisors (see below), whose sum is σ = 17310720. Its totient is φ = 2875176.

The previous prime is 8640427. The next prime is 8640439. The reversal of 8640438 is 8340468.

It is an Ulam number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 8640399 and 8640408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8640439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4731 + ... + 6297.

It is an arithmetic number, because the mean of its divisors is an integer number (1081920).

Almost surely, 2^8640438 is an apocalyptic number.

8640438 is an abundant number, since it is smaller than the sum of its proper divisors (8670282).

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

8640438 is a wasteful number, since it uses less digits than its factorization.

8640438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2491.

The product of its (nonzero) digits is 18432, while the sum is 33.

The square root of 8640438 is about 2939.4621957086. The cubic root of 8640438 is about 205.2005809938.

The spelling of 8640438 in words is "eight million, six hundred forty thousand, four hundred thirty-eight".