665036161 has 4 divisors (see below), whose sum is σ = 665444052. Its totient is φ = 664628272.

The previous prime is 665036159. The next prime is 665036167. The reversal of 665036161 is 161630566.

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 367680625 + 297355536 = 19175^2 + 17244^2 .

It is a cyclic number.

It is not a de Polignac number, because 665036161 - 2¹ = 665036159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665036167) 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, 201490 + ... + 204763.

It is an arithmetic number, because the mean of its divisors is an integer number (166361013).

Almost surely, 2^665036161 is an apocalyptic number.

It is an amenable number.

665036161 is a deficient number, since it is larger than the sum of its proper divisors (407891).

665036161 is a wasteful number, since it uses less digits than its factorization.

665036161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407890.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 665036161 is about 25788.2950386411. The cubic root of 665036161 is about 872.8676943830.

The spelling of 665036161 in words is "six hundred sixty-five million, thirty-six thousand, one hundred sixty-one".