645075 has 36 divisors (see below), whose sum is σ = 1199328. Its totient is φ = 331200.

The previous prime is 645067. The next prime is 645077. The reversal of 645075 is 570546.

It is not a de Polignac number, because 645075 - 2³ = 645067 is a prime.

It is a super-2 number, since 2×645075² = 832243511250, which contains 22 as substring.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (645077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10545 + ... + 10605.

2⁶⁴⁵⁰⁷⁵ is an apocalyptic number.

645075 is a deficient number, since it is larger than the sum of its proper divisors (554253).

645075 is a wasteful number, since it uses less digits than its factorization.

645075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 645075 is about 803.1656118137. The cubic root of 645075 is about 86.4045747321.

Subtracting from 645075 its reverse (570546), we obtain a square (74529 = 273²).

The spelling of 645075 in words is "six hundred forty-five thousand, seventy-five".