640055540 has 12 divisors (see below), whose sum is σ = 1344116676. Its totient is φ = 256022208.

The previous prime is 640055497. The next prime is 640055587. The reversal of 640055540 is 45550046.

640055540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 316199524 + 323856016 = 17782^2 + 17996^2 .

It is a congruent number.

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, 16001369 + ... + 16001408.

It is an arithmetic number, because the mean of its divisors is an integer number (112009723).

Almost surely, 2^640055540 is an apocalyptic number.

It is an amenable number.

640055540 is an abundant number, since it is smaller than the sum of its proper divisors (704061136).

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

640055540 is a wasteful number, since it uses less digits than its factorization.

640055540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32002786 (or 32002784 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 29.

The square root of 640055540 is about 25299.3189631658. The cubic root of 640055540 is about 861.7988038964.

The spelling of 640055540 in words is "six hundred forty million, fifty-five thousand, five hundred forty".