663188661 has 8 divisors (see below), whose sum is σ = 982501760. Its totient is φ = 442125756.

The previous prime is 663188651. The next prime is 663188663. The reversal of 663188661 is 166881366.

663188661 is a `hidden beast` number, since 6 + 631 + 8 + 8 + 6 + 6 + 1 = 666.

It is not a de Polignac number, because 663188661 - 2²⁶ = 596079797 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 (663188663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12281245 + ... + 12281298.

It is an arithmetic number, because the mean of its divisors is an integer number (122812720).

Almost surely, 2^663188661 is an apocalyptic number.

It is an amenable number.

663188661 is a deficient number, since it is larger than the sum of its proper divisors (319313099).

663188661 is a wasteful number, since it uses less digits than its factorization.

663188661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24562552 (or 24562546 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 663188661 is about 25752.4496116389. The cubic root of 663188661 is about 872.0586563277.

The spelling of 663188661 in words is "six hundred sixty-three million, one hundred eighty-eight thousand, six hundred sixty-one".