261445 has 4 divisors (see below), whose sum is σ = 313740. Its totient is φ = 209152.

The previous prime is 261439. The next prime is 261451. The reversal of 261445 is 544162.

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

It is an interprime number because it is at equal distance from previous prime (261439) and next prime (261451).

It can be written as a sum of positive squares in 2 ways, for example, as 103041 + 158404 = 321^2 + 398^2 .

It is a cyclic number.

It is not a de Polignac number, because 261445 - 2¹¹ = 259397 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26140 + ... + 26149.

It is an arithmetic number, because the mean of its divisors is an integer number (78435).

2²⁶¹⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

261445 is a deficient number, since it is larger than the sum of its proper divisors (52295).

261445 is an equidigital number, since it uses as much as digits as its factorization.

261445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52294.

The product of its digits is 960, while the sum is 22.

The square root of 261445 is about 511.3169271597. The cubic root of 261445 is about 63.9430645988.

The spelling of 261445 in words is "two hundred sixty-one thousand, four hundred forty-five".