645851173 has 12 divisors (see below), whose sum is σ = 747268480. Its totient is φ = 556233480.

The previous prime is 645851119. The next prime is 645851183. The reversal of 645851173 is 371158546.

It is a happy number.

It is not a de Polignac number, because 645851173 - 2²¹ = 643754021 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645851183) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 138165 + ... + 142762.

Almost surely, 2^645851173 is an apocalyptic number.

It is an amenable number.

645851173 is a deficient number, since it is larger than the sum of its proper divisors (101417307).

645851173 is a wasteful number, since it uses less digits than its factorization.

645851173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280968 (or 280957 counting only the distinct ones).

The product of its digits is 100800, while the sum is 40.

The square root of 645851173 is about 25413.6021256334. The cubic root of 645851173 is about 864.3921567448.

The spelling of 645851173 in words is "six hundred forty-five million, eight hundred fifty-one thousand, one hundred seventy-three".