645170 has 16 divisors (see below), whose sum is σ = 1171800. Its totient is φ = 255744.

The previous prime is 645149. The next prime is 645179. The reversal of 645170 is 71546.

It can be written as a sum of positive squares in 4 ways, for example, as 247009 + 398161 = 497^2 + 631^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (645179) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1274 + ... + 1706.

2⁶⁴⁵¹⁷⁰ is an apocalyptic number.

645170 is a deficient number, since it is larger than the sum of its proper divisors (526630).

645170 is a wasteful number, since it uses less digits than its factorization.

645170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 645170 is about 803.2247506147. The cubic root of 645170 is about 86.4088161157.

The spelling of 645170 in words is "six hundred forty-five thousand, one hundred seventy".