645787789 has 8 divisors (see below), whose sum is σ = 719763840. Its totient is φ = 575810496.

The previous prime is 645787783. The next prime is 645787817. The reversal of 645787789 is 987787546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645787789 - 2⁵ = 645787757 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 (645787783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 999349 + ... + 999994.

It is an arithmetic number, because the mean of its divisors is an integer number (89970480).

Almost surely, 2^645787789 is an apocalyptic number.

It is an amenable number.

645787789 is a deficient number, since it is larger than the sum of its proper divisors (73976051).

645787789 is a wasteful number, since it uses less digits than its factorization.

645787789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999379.

The product of its digits is 23708160, while the sum is 61.

The square root of 645787789 is about 25412.3550463156. The cubic root of 645787789 is about 864.3638785969.

The spelling of 645787789 in words is "six hundred forty-five million, seven hundred eighty-seven thousand, seven hundred eighty-nine".