665055161 has 4 divisors (see below), whose sum is σ = 665311524. Its totient is φ = 664798800.

The previous prime is 665055133. The next prime is 665055197. The reversal of 665055161 is 161550566.

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

It can be written as a sum of positive squares in 2 ways, for example, as 359329936 + 305725225 = 18956^2 + 17485^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665055161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665051161) 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, 124250 + ... + 129491.

It is an arithmetic number, because the mean of its divisors is an integer number (166327881).

Almost surely, 2^665055161 is an apocalyptic number.

It is an amenable number.

665055161 is a deficient number, since it is larger than the sum of its proper divisors (256363).

665055161 is a wasteful number, since it uses less digits than its factorization.

665055161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256362.

The product of its (nonzero) digits is 27000, while the sum is 35.

The square root of 665055161 is about 25788.6634201930. The cubic root of 665055161 is about 872.8760068775.

The spelling of 665055161 in words is "six hundred sixty-five million, fifty-five thousand, one hundred sixty-one".