261217 has 4 divisors (see below), whose sum is σ = 284976. Its totient is φ = 237460.

The previous prime is 261169. The next prime is 261223. The reversal of 261217 is 712162.

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 261217 - 2⁷ = 261089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261194 and 261203.

It is not an unprimeable number, because it can be changed into a prime (261017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11863 + ... + 11884.

It is an arithmetic number, because the mean of its divisors is an integer number (71244).

2²⁶¹²¹⁷ is an apocalyptic number.

It is an amenable number.

261217 is a deficient number, since it is larger than the sum of its proper divisors (23759).

261217 is a wasteful number, since it uses less digits than its factorization.

261217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23758.

The product of its digits is 168, while the sum is 19.

The square root of 261217 is about 511.0939248318. The cubic root of 261217 is about 63.9244714482.

Adding to 261217 its reverse (712162), we get a palindrome (973379).

The spelling of 261217 in words is "two hundred sixty-one thousand, two hundred seventeen".