645489 has 20 divisors (see below), whose sum is σ = 1040116. Its totient is φ = 396576.

The previous prime is 645481. The next prime is 645493. The reversal of 645489 is 984546.

645489 is a `hidden beast` number, since 645 + 4 + 8 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 32400 + 613089 = 180^2 + 783^2 .

It is not a de Polignac number, because 645489 - 2³ = 645481 is a prime.

It is a Duffinian number.

645489 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (645481) 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 19 ways as a sum of consecutive naturals, for example, 747 + ... + 1359.

2⁶⁴⁵⁴⁸⁹ is an apocalyptic number.

It is an amenable number.

645489 is a deficient number, since it is larger than the sum of its proper divisors (394627).

645489 is a wasteful number, since it uses less digits than its factorization.

645489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638 (or 629 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 645489 is about 803.4233006330. The cubic root of 645489 is about 86.4230551899.

The spelling of 645489 in words is "six hundred forty-five thousand, four hundred eighty-nine".