640700040 has 128 divisors (see below), whose sum is σ = 1975881600. Its totient is φ = 166133760.

The previous prime is 640700003. The next prime is 640700041. The reversal of 640700040 is 40007046.

It is not an unprimeable number, because it can be changed into a prime (640700041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 832776 + ... + 833544.

It is an arithmetic number, because the mean of its divisors is an integer number (15436575).

Almost surely, 2^640700040 is an apocalyptic number.

640700040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640700040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987940800).

640700040 is an abundant number, since it is smaller than the sum of its proper divisors (1335181560).

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

640700040 is a wasteful number, since it uses less digits than its factorization.

640700040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 967 (or 963 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 640700040 is about 25312.0532553169. The cubic root of 640700040 is about 862.0879678673.

Adding to 640700040 its reverse (40007046), we get a palindrome (680707086).

The spelling of 640700040 in words is "six hundred forty million, seven hundred thousand, forty".