660645 has 24 divisors (see below), whose sum is σ = 1170936. Its totient is φ = 344448.

The previous prime is 660643. The next prime is 660659. The reversal of 660645 is 546066.

660645 is digitally balanced in base 7, 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 4 ways, for example, as 42849 + 617796 = 207^2 + 786^2 .

It is not a de Polignac number, because 660645 - 2¹ = 660643 is a prime.

660645 is strictly pandigital in base 7.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 660645.

It is not an unprimeable number, because it can be changed into a prime (660643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2247 + ... + 2523.

It is an arithmetic number, because the mean of its divisors is an integer number (48789).

2⁶⁶⁰⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

660645 is a deficient number, since it is larger than the sum of its proper divisors (510291).

660645 is a wasteful number, since it uses less digits than its factorization.

660645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341 (or 338 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 660645 is about 812.8007135824. The cubic root of 660645 is about 87.0942300465.

The spelling of 660645 in words is "six hundred sixty thousand, six hundred forty-five".