640453 has 12 divisors (see below), whose sum is σ = 723520. Its totient is φ = 566280.

The previous prime is 640421. The next prime is 640457. The reversal of 640453 is 354046.

640453 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640453 - 2⁵ = 640421 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 (640457) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8068 + ... + 8146.

2⁶⁴⁰⁴⁵³ is an apocalyptic number.

It is an amenable number.

640453 is a deficient number, since it is larger than the sum of its proper divisors (83067).

640453 is a wasteful number, since it uses less digits than its factorization.

640453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168 (or 157 counting only the distinct ones).

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

The square root of 640453 is about 800.2830749179. The cubic root of 640453 is about 86.1977152834.

Adding to 640453 its reverse (354046), we get a palindrome (994499).

The spelling of 640453 in words is "six hundred forty thousand, four hundred fifty-three".