261536163 has 16 divisors (see below), whose sum is σ = 399168000. Its totient is φ = 149210496.

The previous prime is 261536161. The next prime is 261536189. The reversal of 261536163 is 361635162.

It is not a de Polignac number, because 261536163 - 2¹ = 261536161 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261536161) 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 15 ways as a sum of consecutive naturals, for example, 3963 + ... + 23211.

It is an arithmetic number, because the mean of its divisors is an integer number (24948000).

Almost surely, 2^261536163 is an apocalyptic number.

261536163 is a deficient number, since it is larger than the sum of its proper divisors (137631837).

261536163 is a wasteful number, since it uses less digits than its factorization.

261536163 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19906.

The product of its digits is 19440, while the sum is 33.

The square root of 261536163 is about 16172.0797363852. The cubic root of 261536163 is about 639.5049581655.

The spelling of 261536163 in words is "two hundred sixty-one million, five hundred thirty-six thousand, one hundred sixty-three".