665507161 has 4 divisors (see below), whose sum is σ = 726007824. Its totient is φ = 605006500.

The previous prime is 665507131. The next prime is 665507207. The reversal of 665507161 is 161705566.

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 665507161 - 2⁷ = 665507033 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665507161.

It is not an unprimeable number, because it can be changed into a prime (665507111) 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, 30250315 + ... + 30250336.

It is an arithmetic number, because the mean of its divisors is an integer number (181501956).

Almost surely, 2^665507161 is an apocalyptic number.

It is an amenable number.

665507161 is a deficient number, since it is larger than the sum of its proper divisors (60500663).

665507161 is a wasteful number, since it uses less digits than its factorization.

665507161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60500662.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 665507161 is about 25797.4254723218. The cubic root of 665507161 is about 873.0737100806.

The spelling of 665507161 in words is "six hundred sixty-five million, five hundred seven thousand, one hundred sixty-one".