261923 has 4 divisors (see below), whose sum is σ = 269040. Its totient is φ = 254808.

The previous prime is 261917. The next prime is 261959. The reversal of 261923 is 329162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 329162 = 2 ⋅164581.

It is a cyclic number.

It is not a de Polignac number, because 261923 - 2¹⁶ = 196387 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (261973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3503 + ... + 3576.

It is an arithmetic number, because the mean of its divisors is an integer number (67260).

2²⁶¹⁹²³ is an apocalyptic number.

261923 is a deficient number, since it is larger than the sum of its proper divisors (7117).

261923 is an equidigital number, since it uses as much as digits as its factorization.

261923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7116.

The product of its digits is 648, while the sum is 23.

The square root of 261923 is about 511.7841341816. The cubic root of 261923 is about 63.9820099175.

The spelling of 261923 in words is "two hundred sixty-one thousand, nine hundred twenty-three".