645171229 has 4 divisors (see below), whose sum is σ = 673222176. Its totient is φ = 617120284.

The previous prime is 645171221. The next prime is 645171251. The reversal of 645171229 is 922171546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 922171546 = 2 ⋅461085773.

It is a cyclic number.

It is not a de Polignac number, because 645171229 - 2³ = 645171221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645171221) 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 3 ways as a sum of consecutive naturals, for example, 14025439 + ... + 14025484.

It is an arithmetic number, because the mean of its divisors is an integer number (168305544).

Almost surely, 2^645171229 is an apocalyptic number.

It is an amenable number.

645171229 is a deficient number, since it is larger than the sum of its proper divisors (28050947).

645171229 is a wasteful number, since it uses less digits than its factorization.

645171229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28050946.

The product of its digits is 30240, while the sum is 37.

The square root of 645171229 is about 25400.2210423453. The cubic root of 645171229 is about 864.0887098309.

The spelling of 645171229 in words is "six hundred forty-five million, one hundred seventy-one thousand, two hundred twenty-nine".