668495161 has 4 divisors (see below), whose sum is σ = 697560192. Its totient is φ = 639430132.

The previous prime is 668495159. The next prime is 668495171. The reversal of 668495161 is 161594866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 668495161 - 2¹ = 668495159 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668495141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14532481 + ... + 14532526.

It is an arithmetic number, because the mean of its divisors is an integer number (174390048).

Almost surely, 2^668495161 is an apocalyptic number.

It is an amenable number.

668495161 is a deficient number, since it is larger than the sum of its proper divisors (29065031).

668495161 is a wasteful number, since it uses less digits than its factorization.

668495161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29065030.

The product of its digits is 311040, while the sum is 46.

The square root of 668495161 is about 25855.2733692761. The cubic root of 668495161 is about 874.3784041312.

It can be divided in two parts, 66849 and 5161, that added together give a triangular number (72010 = T₃₇₉).

The spelling of 668495161 in words is "six hundred sixty-eight million, four hundred ninety-five thousand, one hundred sixty-one".