165707561 has 4 divisors (see below), whose sum is σ = 165834324. Its totient is φ = 165580800.

The previous prime is 165707501. The next prime is 165707567.

165707561 is nontrivially palindromic in base 10.

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 92929600 + 72777961 = 9640^2 + 8531^2 .

It is a cyclic number.

It is not a de Polignac number, because 165707561 - 2¹⁴ = 165691177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165707567) 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, 61400 + ... + 64041.

It is an arithmetic number, because the mean of its divisors is an integer number (41458581).

Almost surely, 2^165707561 is an apocalyptic number.

It is an amenable number.

165707561 is a deficient number, since it is larger than the sum of its proper divisors (126763).

165707561 is a wasteful number, since it uses less digits than its factorization.

165707561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126762.

The product of its (nonzero) digits is 44100, while the sum is 38.

The square root of 165707561 is about 12872.7448898827. The cubic root of 165707561 is about 549.2635443460.

The spelling of 165707561 in words is "one hundred sixty-five million, seven hundred seven thousand, five hundred sixty-one".