668706665 has 32 divisors (see below), whose sum is σ = 889574400. Its totient is φ = 478526400.

The previous prime is 668706641. The next prime is 668706683. The reversal of 668706665 is 566607866.

It is not a de Polignac number, because 668706665 - 2⁶ = 668706601 is a prime.

It is an unprimeable number.

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 in 31 ways as a sum of consecutive naturals, for example, 1170830 + ... + 1171400.

It is an arithmetic number, because the mean of its divisors is an integer number (27799200).

Almost surely, 2^668706665 is an apocalyptic number.

It is an amenable number.

668706665 is a deficient number, since it is larger than the sum of its proper divisors (220867735).

668706665 is a wasteful number, since it uses less digits than its factorization.

668706665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893.

The product of its (nonzero) digits is 2177280, while the sum is 50.

The square root of 668706665 is about 25859.3631978825. The cubic root of 668706665 is about 874.4706087527.

The spelling of 668706665 in words is "six hundred sixty-eight million, seven hundred six thousand, six hundred sixty-five".