640145 has 16 divisors (see below), whose sum is σ = 853632. Its totient is φ = 456960.

The previous prime is 640139. The next prime is 640151. The reversal of 640145 is 541046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640139) and next prime (640151).

It is a de Polignac number, because none of the positive numbers 2^k-640145 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5609 + ... + 5721.

It is an arithmetic number, because the mean of its divisors is an integer number (53352).

2⁶⁴⁰¹⁴⁵ is an apocalyptic number.

It is an amenable number.

640145 is a deficient number, since it is larger than the sum of its proper divisors (213487).

640145 is a wasteful number, since it uses less digits than its factorization.

640145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 640145 is about 800.0906198675. The cubic root of 640145 is about 86.1838952980.

Subtracting from 640145 its reverse (541046), we obtain a palindrome (99099).

It can be divided in two parts, 6401 and 45, that added together give a palindrome (6446).

The spelling of 640145 in words is "six hundred forty thousand, one hundred forty-five".