640045 has 8 divisors (see below), whose sum is σ = 877824. Its totient is φ = 438864.

The previous prime is 640043. The next prime is 640049. The reversal of 640045 is 540046.

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 640045 - 2¹ = 640043 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9109 + ... + 9178.

It is an arithmetic number, because the mean of its divisors is an integer number (109728).

2⁶⁴⁰⁰⁴⁵ is an apocalyptic number.

It is an amenable number.

640045 is a deficient number, since it is larger than the sum of its proper divisors (237779).

640045 is a wasteful number, since it uses less digits than its factorization.

640045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18299.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 640045 is about 800.0281245056. The cubic root of 640045 is about 86.1794073365.

Subtracting from 640045 its reverse (540046), we obtain a palindrome (99999).

It can be divided in two parts, 64004 and 5, that added together give a square (64009 = 253²).

The spelling of 640045 in words is "six hundred forty thousand, forty-five".