640545 has 8 divisors (see below), whose sum is σ = 1024896. Its totient is φ = 341616.

The previous prime is 640531. The next prime is 640579. The reversal of 640545 is 545046.

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

It is not a de Polignac number, because 640545 - 2⁴ = 640529 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640545.

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, 21337 + ... + 21366.

It is an arithmetic number, because the mean of its divisors is an integer number (128112).

2⁶⁴⁰⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

640545 is a deficient number, since it is larger than the sum of its proper divisors (384351).

640545 is a wasteful number, since it uses less digits than its factorization.

640545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42711.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 640545 is about 800.3405525150. The cubic root of 640545 is about 86.2018424715.

The spelling of 640545 in words is "six hundred forty thousand, five hundred forty-five".