261311 has 8 divisors (see below), whose sum is σ = 274560. Its totient is φ = 248472.

The previous prime is 261301. The next prime is 261323. The reversal of 261311 is 113162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2486 + ... + 2588.

It is an arithmetic number, because the mean of its divisors is an integer number (34320).

2²⁶¹³¹¹ is an apocalyptic number.

261311 is a deficient number, since it is larger than the sum of its proper divisors (13249).

261311 is a wasteful number, since it uses less digits than its factorization.

261311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205.

The product of its digits is 36, while the sum is 14.

The square root of 261311 is about 511.1858761742. The cubic root of 261311 is about 63.9321383556.

Adding to 261311 its reverse (113162), we get a palindrome (374473).

The spelling of 261311 in words is "two hundred sixty-one thousand, three hundred eleven".