664655161 has 4 divisors (see below), whose sum is σ = 682618852. Its totient is φ = 646691472.

The previous prime is 664655143. The next prime is 664655179. The reversal of 664655161 is 161556466.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (664655143) and next prime (664655179).

It can be written as a sum of positive squares in 2 ways, for example, as 509901561 + 154753600 = 22581^2 + 12440^2 .

It is a cyclic number.

It is not a de Polignac number, because 664655161 - 2²³ = 656266553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664655111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8981790 + ... + 8981863.

It is an arithmetic number, because the mean of its divisors is an integer number (170654713).

Almost surely, 2^664655161 is an apocalyptic number.

It is an amenable number.

664655161 is a deficient number, since it is larger than the sum of its proper divisors (17963691).

664655161 is a wasteful number, since it uses less digits than its factorization.

664655161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17963690.

The product of its digits is 129600, while the sum is 40.

The square root of 664655161 is about 25780.9069080201. The cubic root of 664655161 is about 872.7009735640.

The spelling of 664655161 in words is "six hundred sixty-four million, six hundred fifty-five thousand, one hundred sixty-one".