261718 has 4 divisors (see below), whose sum is σ = 392580. Its totient is φ = 130858.

The previous prime is 261713. The next prime is 261721. The reversal of 261718 is 817162.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 261692 and 261701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65428 + ... + 65431.

It is an arithmetic number, because the mean of its divisors is an integer number (98145).

261718 is a Friedman number, since it can be written as 2^18-71*6, using all its digits and the basic arithmetic operations.

2²⁶¹⁷¹⁸ is an apocalyptic number.

261718 is a deficient number, since it is larger than the sum of its proper divisors (130862).

261718 is a wasteful number, since it uses less digits than its factorization.

261718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130861.

The product of its digits is 672, while the sum is 25.

The square root of 261718 is about 511.5838152248. The cubic root of 261718 is about 63.9653132351.

It can be divided in two parts, 261 and 718, that added together give a palindrome (979).

The spelling of 261718 in words is "two hundred sixty-one thousand, seven hundred eighteen".