640365 has 16 divisors (see below), whose sum is σ = 1118016. Its totient is φ = 310400.

The previous prime is 640363. The next prime is 640369. The reversal of 640365 is 563046.

It is not a de Polignac number, because 640365 - 2¹ = 640363 is a prime.

640365 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640365.

It is not an unprimeable number, because it can be changed into a prime (640363) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1776 + ... + 2105.

It is an arithmetic number, because the mean of its divisors is an integer number (69876).

2⁶⁴⁰³⁶⁵ is an apocalyptic number.

It is an amenable number.

640365 is a deficient number, since it is larger than the sum of its proper divisors (477651).

640365 is a wasteful number, since it uses less digits than its factorization.

640365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3900.

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 640365 is about 800.2280924836. The cubic root of 640365 is about 86.1937671683.

The spelling of 640365 in words is "six hundred forty thousand, three hundred sixty-five".