840040 has 16 divisors (see below), whose sum is σ = 1890180. Its totient is φ = 336000.

The previous prime is 840023. The next prime is 840053. The reversal of 840040 is 40048.

It can be written as a sum of positive squares in 2 ways, for example, as 799236 + 40804 = 894^2 + 202^2 .

It is a junction number, because it is equal to n+sod(n) for n = 839996 and 840023.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10461 + ... + 10540.

2⁸⁴⁰⁰⁴⁰ is an apocalyptic number.

It is an amenable number.

840040 is an abundant number, since it is smaller than the sum of its proper divisors (1050140).

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

840040 is a wasteful number, since it uses less digits than its factorization.

840040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21012 (or 21008 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 840040 is about 916.5369605204. The cubic root of 840040 is about 94.3553772632.

Adding to 840040 its reverse (40048), we get a palindrome (880088).

The spelling of 840040 in words is "eight hundred forty thousand, forty".