645770 has 8 divisors (see below), whose sum is σ = 1162404. Its totient is φ = 258304.

The previous prime is 645763. The next prime is 645787. The reversal of 645770 is 77546.

645770 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 644809 + 961 = 803^2 + 31^2 .

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

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645770.

It is an unprimeable number.

645770 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32279 + ... + 32298.

2⁶⁴⁵⁷⁷⁰ is an apocalyptic number.

645770 is a deficient number, since it is larger than the sum of its proper divisors (516634).

645770 is a wasteful number, since it uses less digits than its factorization.

645770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64584.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 645770 is about 803.5981582856. The cubic root of 645770 is about 86.4355941877.

The spelling of 645770 in words is "six hundred forty-five thousand, seven hundred seventy".