265163561 has 4 divisors (see below), whose sum is σ = 285560772. Its totient is φ = 244766352.

The previous prime is 265163557. The next prime is 265163567. The reversal of 265163561 is 165361562.

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 10601536 + 254562025 = 3256^2 + 15955^2 .

It is a cyclic number.

It is not a de Polignac number, because 265163561 - 2² = 265163557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (265163567) 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, 10198586 + ... + 10198611.

It is an arithmetic number, because the mean of its divisors is an integer number (71390193).

Almost surely, 2^265163561 is an apocalyptic number.

It is an amenable number.

265163561 is a deficient number, since it is larger than the sum of its proper divisors (20397211).

265163561 is a wasteful number, since it uses less digits than its factorization.

265163561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20397210.

The product of its digits is 32400, while the sum is 35.

The square root of 265163561 is about 16283.8435573424. The cubic root of 265163561 is about 642.4479498781.

The spelling of 265163561 in words is "two hundred sixty-five million, one hundred sixty-three thousand, five hundred sixty-one".