645670 has 8 divisors (see below), whose sum is σ = 1162224. Its totient is φ = 258264.

The previous prime is 645661. The next prime is 645683. The reversal of 645670 is 76546.

645670 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32274 + ... + 32293.

It is an arithmetic number, because the mean of its divisors is an integer number (145278).

2⁶⁴⁵⁶⁷⁰ is an apocalyptic number.

645670 is a deficient number, since it is larger than the sum of its proper divisors (516554).

645670 is a wasteful number, since it uses less digits than its factorization.

645670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64574.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 645670 is about 803.5359357241. The cubic root of 645670 is about 86.4311323279.

The spelling of 645670 in words is "six hundred forty-five thousand, six hundred seventy".