645795109 has 4 divisors (see below), whose sum is σ = 646248460. Its totient is φ = 645341760.

The previous prime is 645795097. The next prime is 645795169. The reversal of 645795109 is 901597546.

645795109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 306425025 + 339370084 = 17505^2 + 18422^2 .

It is a cyclic number.

It is not a de Polignac number, because 645795109 - 2¹¹ = 645793061 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 (645795169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224532 + ... + 227389.

It is an arithmetic number, because the mean of its divisors is an integer number (161562115).

Almost surely, 2^645795109 is an apocalyptic number.

It is an amenable number.

645795109 is a deficient number, since it is larger than the sum of its proper divisors (453351).

645795109 is a wasteful number, since it uses less digits than its factorization.

645795109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453350.

The product of its (nonzero) digits is 340200, while the sum is 46.

The square root of 645795109 is about 25412.4990703394. The cubic root of 645795109 is about 864.3671444374.

The spelling of 645795109 in words is "six hundred forty-five million, seven hundred ninety-five thousand, one hundred nine".