640543040 has 28 divisors (see below), whose sum is σ = 1525293876. Its totient is φ = 256217088.

The previous prime is 640543019. The next prime is 640543061. The reversal of 640543040 is 40345046.

It is an interprime number because it is at equal distance from previous prime (640543019) and next prime (640543061).

It can be written as a sum of positive squares in 2 ways, for example, as 115949824 + 524593216 = 10768^2 + 22904^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1000529 + ... + 1001168.

Almost surely, 2^640543040 is an apocalyptic number.

It is an amenable number.

640543040 is an abundant number, since it is smaller than the sum of its proper divisors (884750836).

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

640543040 is a wasteful number, since it uses less digits than its factorization.

640543040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2001714 (or 2001704 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 26.

The square root of 640543040 is about 25308.9517760021. The cubic root of 640543040 is about 862.0175454858.

Adding to 640543040 its reverse (40345046), we get a palindrome (680888086).

The spelling of 640543040 in words is "six hundred forty million, five hundred forty-three thousand, forty".