261393 has 12 divisors (see below), whose sum is σ = 384528. Its totient is φ = 156640.

The previous prime is 261389. The next prime is 261407. The reversal of 261393 is 393162.

It is not a de Polignac number, because 261393 - 2² = 261389 is a prime.

It is a Curzon number.

261393 is a lucky number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (261323) 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 11 ways as a sum of consecutive naturals, for example, 2893 + ... + 2981.

It is an arithmetic number, because the mean of its divisors is an integer number (32044).

2²⁶¹³⁹³ is an apocalyptic number.

It is an amenable number.

261393 is a deficient number, since it is larger than the sum of its proper divisors (123135).

261393 is an equidigital number, since it uses as much as digits as its factorization.

261393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 103 counting only the distinct ones).

The product of its digits is 972, while the sum is 24.

The square root of 261393 is about 511.2660755419. The cubic root of 261393 is about 63.9388250075.

Subtracting 261393 from its reverse (393162), we obtain a square (131769 = 363²).

The spelling of 261393 in words is "two hundred sixty-one thousand, three hundred ninety-three".