645506 has 8 divisors (see below), whose sum is σ = 1019280. Its totient is φ = 305748.

The previous prime is 645503. The next prime is 645521. The reversal of 645506 is 605546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645506.

It is not an unprimeable number, because it can be changed into a prime (645503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8456 + ... + 8531.

It is an arithmetic number, because the mean of its divisors is an integer number (127410).

2⁶⁴⁵⁵⁰⁶ is an apocalyptic number.

645506 is a deficient number, since it is larger than the sum of its proper divisors (373774).

645506 is a wasteful number, since it uses less digits than its factorization.

645506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17008.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 645506 is about 803.4338802913. The cubic root of 645506 is about 86.4238138804.

The spelling of 645506 in words is "six hundred forty-five thousand, five hundred six".