663128191 has 4 divisors (see below), whose sum is σ = 723412584. Its totient is φ = 602843800.

The previous prime is 663128189. The next prime is 663128261. The reversal of 663128191 is 191821366.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 663128191 - 2¹ = 663128189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 663128191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663125191) 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, 30142180 + ... + 30142201.

It is an arithmetic number, because the mean of its divisors is an integer number (180853146).

Almost surely, 2^663128191 is an apocalyptic number.

663128191 is a deficient number, since it is larger than the sum of its proper divisors (60284393).

663128191 is a wasteful number, since it uses less digits than its factorization.

663128191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60284392.

The product of its digits is 15552, while the sum is 37.

The square root of 663128191 is about 25751.2755218067. The cubic root of 663128191 is about 872.0321505520.

The spelling of 663128191 in words is "six hundred sixty-three million, one hundred twenty-eight thousand, one hundred ninety-one".