668555887 has 2 divisors, whose sum is σ = 668555888. Its totient is φ = 668555886.

The previous prime is 668555863. The next prime is 668555933. The reversal of 668555887 is 788555866.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668555887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668555837) 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, 334277943 + 334277944.

It is an arithmetic number, because the mean of its divisors is an integer number (334277944).

Almost surely, 2^668555887 is an apocalyptic number.

668555887 is a deficient number, since it is larger than the sum of its proper divisors (1).

668555887 is an equidigital number, since it uses as much as digits as its factorization.

668555887 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128000, while the sum is 58.

The square root of 668555887 is about 25856.4476871824. The cubic root of 668555887 is about 874.4048794639.

The spelling of 668555887 in words is "six hundred sixty-eight million, five hundred fifty-five thousand, eight hundred eighty-seven".