261247 has 4 divisors (see below), whose sum is σ = 298576. Its totient is φ = 223920.

The previous prime is 261241. The next prime is 261251. The reversal of 261247 is 742162.

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

It is a cyclic number.

It is not a de Polignac number, because 261247 - 2¹⁵ = 228479 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261241) 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, 18654 + ... + 18667.

It is an arithmetic number, because the mean of its divisors is an integer number (74644).

2²⁶¹²⁴⁷ is an apocalyptic number.

261247 is a deficient number, since it is larger than the sum of its proper divisors (37329).

261247 is an equidigital number, since it uses as much as digits as its factorization.

261247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37328.

The product of its digits is 672, while the sum is 22.

The square root of 261247 is about 511.1232728022. The cubic root of 261247 is about 63.9269185333.

The spelling of 261247 in words is "two hundred sixty-one thousand, two hundred forty-seven".