670645 has 4 divisors (see below), whose sum is σ = 804780. Its totient is φ = 536512.

The previous prime is 670639. The next prime is 670669. The reversal of 670645 is 546076.

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 272484 + 398161 = 522^2 + 631^2 .

It is a cyclic number.

It is not a de Polignac number, because 670645 - 2⁵ = 670613 is a prime.

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, 67060 + ... + 67069.

It is an arithmetic number, because the mean of its divisors is an integer number (201195).

2⁶⁷⁰⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

670645 is a deficient number, since it is larger than the sum of its proper divisors (134135).

670645 is a wasteful number, since it uses less digits than its factorization.

670645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134134.

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

The square root of 670645 is about 818.9291788671. The cubic root of 670645 is about 87.5314716722.

The spelling of 670645 in words is "six hundred seventy thousand, six hundred forty-five".