261335533163 has 4 divisors (see below), whose sum is σ = 261336579048. Its totient is φ = 261334487280.

The previous prime is 261335533141. The next prime is 261335533183. The reversal of 261335533163 is 361335533162.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 261335533163 - 2²⁴ = 261318755947 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 261335533163.

It is not an unprimeable number, because it can be changed into a prime (261335533133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96248 + ... + 729338.

It is an arithmetic number, because the mean of its divisors is an integer number (65334144762).

Almost surely, 2^261335533163 is an apocalyptic number.

261335533163 is a deficient number, since it is larger than the sum of its proper divisors (1045885).

261335533163 is an equidigital number, since it uses as much as digits as its factorization.

261335533163 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1045884.

The product of its digits is 437400, while the sum is 41.

Subtracting 261335533163 from its reverse (361335533162), we obtain a palindrome (99999999999).

The spelling of 261335533163 in words is "two hundred sixty-one billion, three hundred thirty-five million, five hundred thirty-three thousand, one hundred sixty-three".