645603 has 16 divisors (see below), whose sum is σ = 999936. Its totient is φ = 362880.

The previous prime is 645599. The next prime is 645611. The reversal of 645603 is 306546.

645603 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645603 - 2² = 645599 is a prime.

645603 is strictly pandigital in base 7.

It is not an unprimeable number, because it can be changed into a prime (645683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1275 + ... + 1707.

It is an arithmetic number, because the mean of its divisors is an integer number (62496).

2⁶⁴⁵⁶⁰³ is an apocalyptic number.

645603 is a deficient number, since it is larger than the sum of its proper divisors (354333).

645603 is a wasteful number, since it uses less digits than its factorization.

645603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514.

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 645603 is about 803.4942439122. The cubic root of 645603 is about 86.4281426241.

The spelling of 645603 in words is "six hundred forty-five thousand, six hundred three".