640289655 has 48 divisors (see below), whose sum is σ = 1150466304. Its totient is φ = 329080320.

The previous prime is 640289647. The next prime is 640289681. The reversal of 640289655 is 556982046.

640289655 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640289655 - 2³ = 640289647 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 640289655.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 385587 + ... + 387243.

It is an arithmetic number, because the mean of its divisors is an integer number (23968048).

Almost surely, 2^640289655 is an apocalyptic number.

640289655 is a deficient number, since it is larger than the sum of its proper divisors (510176649).

640289655 is a wasteful number, since it uses less digits than its factorization.

640289655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1976 (or 1973 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 640289655 is about 25303.9454433493. The cubic root of 640289655 is about 861.9038653168.

The spelling of 640289655 in words is "six hundred forty million, two hundred eighty-nine thousand, six hundred fifty-five".