668140665 has 32 divisors (see below), whose sum is σ = 1098510336. Its totient is φ = 346584000.

The previous prime is 668140609. The next prime is 668140699. The reversal of 668140665 is 566041866.

668140665 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 668140665 - 2¹⁵ = 668107897 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 159832 + ... + 163958.

It is an arithmetic number, because the mean of its divisors is an integer number (34328448).

Almost surely, 2^668140665 is an apocalyptic number.

It is an amenable number.

668140665 is a deficient number, since it is larger than the sum of its proper divisors (430369671).

668140665 is a wasteful number, since it uses less digits than its factorization.

668140665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4429.

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 668140665 is about 25848.4170695228. The cubic root of 668140665 is about 874.2238188921.

The spelling of 668140665 in words is "six hundred sixty-eight million, one hundred forty thousand, six hundred sixty-five".