261711161 has 4 divisors (see below), whose sum is σ = 261808512. Its totient is φ = 261613812.

The previous prime is 261711157. The next prime is 261711173. The reversal of 261711161 is 161117162.

It is a happy number.

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 261711161 - 2² = 261711157 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 261711161.

It is not an unprimeable number, because it can be changed into a prime (261711061) 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, 44525 + ... + 50058.

It is an arithmetic number, because the mean of its divisors is an integer number (65452128).

Almost surely, 2^261711161 is an apocalyptic number.

It is an amenable number.

261711161 is a deficient number, since it is larger than the sum of its proper divisors (97351).

261711161 is an equidigital number, since it uses as much as digits as its factorization.

261711161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97350.

The product of its digits is 504, while the sum is 26.

The square root of 261711161 is about 16177.4893293119. The cubic root of 261711161 is about 639.6475606721.

The spelling of 261711161 in words is "two hundred sixty-one million, seven hundred eleven thousand, one hundred sixty-one".