663643645 has 8 divisors (see below), whose sum is σ = 910139904. Its totient is φ = 455069904.

The previous prime is 663643577. The next prime is 663643649. The reversal of 663643645 is 546346366.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-663643645 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663643649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9480589 + ... + 9480658.

It is an arithmetic number, because the mean of its divisors is an integer number (113767488).

Almost surely, 2^663643645 is an apocalyptic number.

It is an amenable number.

663643645 is a deficient number, since it is larger than the sum of its proper divisors (246496259).

663643645 is a wasteful number, since it uses less digits than its factorization.

663643645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18961259.

The product of its digits is 933120, while the sum is 43.

The square root of 663643645 is about 25761.2818974522. The cubic root of 663643645 is about 872.2580375182.

The spelling of 663643645 in words is "six hundred sixty-three million, six hundred forty-three thousand, six hundred forty-five".