640339555 has 8 divisors (see below), whose sum is σ = 771624000. Its totient is φ = 510127296.

The previous prime is 640339547. The next prime is 640339571. The reversal of 640339555 is 555933046.

It is a happy number.

640339555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640339555 - 2³ = 640339547 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266730 + ... + 269119.

It is an arithmetic number, because the mean of its divisors is an integer number (96453000).

Almost surely, 2^640339555 is an apocalyptic number.

640339555 is a deficient number, since it is larger than the sum of its proper divisors (131284445).

640339555 is a wasteful number, since it uses less digits than its factorization.

640339555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536093.

The product of its (nonzero) digits is 243000, while the sum is 40.

The square root of 640339555 is about 25304.9314363821. The cubic root of 640339555 is about 861.9262551239.

The spelling of 640339555 in words is "six hundred forty million, three hundred thirty-nine thousand, five hundred fifty-five".