640345 has 8 divisors (see below), whose sum is σ = 778176. Its totient is φ = 505776.

The previous prime is 640333. The next prime is 640363. The reversal of 640345 is 543046.

640345 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 640345 - 2⁹ = 639833 is a prime.

It is a Duffinian number.

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, 357 + ... + 1186.

It is an arithmetic number, because the mean of its divisors is an integer number (97272).

2⁶⁴⁰³⁴⁵ is an apocalyptic number.

It is an amenable number.

640345 is a deficient number, since it is larger than the sum of its proper divisors (137831).

640345 is a wasteful number, since it uses less digits than its factorization.

640345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 640345 is about 800.2155959490. The cubic root of 640345 is about 86.1928698190.

The spelling of 640345 in words is "six hundred forty thousand, three hundred forty-five".