645789 has 8 divisors (see below), whose sum is σ = 866880. Its totient is φ = 427616.

The previous prime is 645787. The next prime is 645803. The reversal of 645789 is 987546.

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 645789 - 2¹ = 645787 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645787) 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, 144 + ... + 1145.

It is an arithmetic number, because the mean of its divisors is an integer number (108360).

2⁶⁴⁵⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

645789 is a deficient number, since it is larger than the sum of its proper divisors (221091).

645789 is a wasteful number, since it uses less digits than its factorization.

645789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1459.

The product of its digits is 60480, while the sum is 39.

The square root of 645789 is about 803.6099800276. The cubic root of 645789 is about 86.4364418890.

The spelling of 645789 in words is "six hundred forty-five thousand, seven hundred eighty-nine".