645175 has 12 divisors (see below), whose sum is σ = 810216. Its totient is φ = 509600.

The previous prime is 645149. The next prime is 645179. The reversal of 645175 is 571546.

It is not a de Polignac number, because 645175 - 2¹³ = 636983 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645179) 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 11 ways as a sum of consecutive naturals, for example, 3177 + ... + 3373.

It is an arithmetic number, because the mean of its divisors is an integer number (67518).

2⁶⁴⁵¹⁷⁵ is an apocalyptic number.

645175 is a deficient number, since it is larger than the sum of its proper divisors (165041).

645175 is a wasteful number, since it uses less digits than its factorization.

645175 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338 (or 333 counting only the distinct ones).

The product of its digits is 4200, while the sum is 28.

The square root of 645175 is about 803.2278630625. The cubic root of 645175 is about 86.4090393349.

It can be divided in two parts, 645 and 175, that added together give a triangular number (820 = T₄₀).

The spelling of 645175 in words is "six hundred forty-five thousand, one hundred seventy-five".