663752813 has 4 divisors (see below), whose sum is σ = 679941948. Its totient is φ = 647563680.

The previous prime is 663752809. The next prime is 663752819. The reversal of 663752813 is 318257366.

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 100260169 + 563492644 = 10013^2 + 23738^2 .

It is a cyclic number.

It is not a de Polignac number, because 663752813 - 2² = 663752809 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 16189093 = 663752813 / (6 + 6 + 3 + 7 + 5 + 2 + 8 + 1 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663752819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8094506 + ... + 8094587.

It is an arithmetic number, because the mean of its divisors is an integer number (169985487).

Almost surely, 2^663752813 is an apocalyptic number.

It is an amenable number.

663752813 is a deficient number, since it is larger than the sum of its proper divisors (16189135).

663752813 is a wasteful number, since it uses less digits than its factorization.

663752813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16189134.

The product of its digits is 181440, while the sum is 41.

The square root of 663752813 is about 25763.4006489827. The cubic root of 663752813 is about 872.3058631072.

The spelling of 663752813 in words is "six hundred sixty-three million, seven hundred fifty-two thousand, eight hundred thirteen".