645545 has 16 divisors (see below), whose sum is σ = 822528. Its totient is φ = 485760.

The previous prime is 645529. The next prime is 645571. The reversal of 645545 is 545546.

It is not a de Polignac number, because 645545 - 2⁴ = 645529 is a prime.

It is a Duffinian number.

Its product of digits (12000) is a multiple of the sum of its prime divisors (160).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645545.

It is an unprimeable number.

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, 9602 + ... + 9668.

It is an arithmetic number, because the mean of its divisors is an integer number (51408).

2⁶⁴⁵⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

645545 is a deficient number, since it is larger than the sum of its proper divisors (176983).

645545 is a wasteful number, since it uses less digits than its factorization.

645545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160.

The product of its digits is 12000, while the sum is 29.

The square root of 645545 is about 803.4581507459. The cubic root of 645545 is about 86.4255543552.

Subtracting from 645545 its reverse (545546), we obtain a palindrome (99999).

The spelling of 645545 in words is "six hundred forty-five thousand, five hundred forty-five".