261853 has 4 divisors (see below), whose sum is σ = 262908. Its totient is φ = 260800.

The previous prime is 261847. The next prime is 261881. The reversal of 261853 is 358162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 182329 + 79524 = 427^2 + 282^2 .

It is a cyclic number.

It is not a de Polignac number, because 261853 - 2¹³ = 253661 is a prime.

It is an Ulam number.

It is a Duffinian number.

261853 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261823) 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, 75 + ... + 727.

It is an arithmetic number, because the mean of its divisors is an integer number (65727).

2²⁶¹⁸⁵³ is an apocalyptic number.

It is an amenable number.

261853 is a deficient number, since it is larger than the sum of its proper divisors (1055).

261853 is an equidigital number, since it uses as much as digits as its factorization.

261853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054.

The product of its digits is 1440, while the sum is 25.

The square root of 261853 is about 511.7157414034. The cubic root of 261853 is about 63.9763095912.

The spelling of 261853 in words is "two hundred sixty-one thousand, eight hundred fifty-three".