668557905 has 32 divisors (see below), whose sum is σ = 1117863936. Its totient is φ = 340553664.

The previous prime is 668557889. The next prime is 668557907. The reversal of 668557905 is 509755866.

668557905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 668557905 - 2⁴ = 668557889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668557907) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 365824 + ... + 367646.

It is an arithmetic number, because the mean of its divisors is an integer number (34933248).

Almost surely, 2^668557905 is an apocalyptic number.

It is an amenable number.

668557905 is a deficient number, since it is larger than the sum of its proper divisors (449306031).

668557905 is a wasteful number, since it uses less digits than its factorization.

668557905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2917.

The product of its (nonzero) digits is 2268000, while the sum is 51.

The square root of 668557905 is about 25856.4867103015. The cubic root of 668557905 is about 874.4057592444.

The spelling of 668557905 in words is "six hundred sixty-eight million, five hundred fifty-seven thousand, nine hundred five".