663645 has 16 divisors (see below), whose sum is σ = 1072512. Its totient is φ = 350400.

The previous prime is 663631. The next prime is 663653. The reversal of 663645 is 546366.

It is not a de Polignac number, because 663645 - 2⁶ = 663581 is a prime.

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 663645.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2119 + ... + 2411.

It is an arithmetic number, because the mean of its divisors is an integer number (67032).

2⁶⁶³⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

663645 is a deficient number, since it is larger than the sum of its proper divisors (408867).

663645 is a wasteful number, since it uses less digits than its factorization.

663645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452.

The product of its digits is 12960, while the sum is 30.

The square root of 663645 is about 814.6440940681. The cubic root of 663645 is about 87.2258631165.

The spelling of 663645 in words is "six hundred sixty-three thousand, six hundred forty-five".