6400040 has 16 divisors (see below), whose sum is σ = 14400180. Its totient is φ = 2560000.

The previous prime is 6400033. The next prime is 6400091. The reversal of 6400040 is 400046.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5769604 + 630436 = 2402^2 + 794^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6399988 and 6400024.

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, 79961 + ... + 80040.

Almost surely, 2^6400040 is an apocalyptic number.

It is an amenable number.

6400040 is an abundant number, since it is smaller than the sum of its proper divisors (8000140).

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

6400040 is a wasteful number, since it uses less digits than its factorization.

6400040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160012 (or 160008 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 6400040 is about 2529.8300338165. The cubic root of 6400040 is about 185.6639401428.

Adding to 6400040 its reverse (400046), we get a palindrome (6800086).

It can be divided in two parts, 64000 and 40, that multiplied together give a 4-th power (2560000 = 40⁴).

The spelling of 6400040 in words is "six million, four hundred thousand, forty".