666563687 has 2 divisors, whose sum is σ = 666563688. Its totient is φ = 666563686.

The previous prime is 666563641. The next prime is 666563707. The reversal of 666563687 is 786365666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666563687 - 2⁸ = 666563431 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666563617) 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 as a sum of consecutive naturals, namely, 333281843 + 333281844.

It is an arithmetic number, because the mean of its divisors is an integer number (333281844).

Almost surely, 2^666563687 is an apocalyptic number.

666563687 is a deficient number, since it is larger than the sum of its proper divisors (1).

666563687 is an equidigital number, since it uses as much as digits as its factorization.

666563687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6531840, while the sum is 53.

The square root of 666563687 is about 25817.8947050297. The cubic root of 666563687 is about 873.5354819075.

The spelling of 666563687 in words is "six hundred sixty-six million, five hundred sixty-three thousand, six hundred eighty-seven".