265981 has 4 divisors (see below), whose sum is σ = 280000. Its totient is φ = 251964.

The previous prime is 265961. The next prime is 265987. The reversal of 265981 is 189562.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 189562 = 2 ⋅94781.

It is a cyclic number.

It is not a de Polignac number, because 265981 - 2¹¹ = 263933 is a prime.

It is a super-2 number, since 2×265981² = 141491784722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (265987) 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 3 ways as a sum of consecutive naturals, for example, 6981 + ... + 7018.

It is an arithmetic number, because the mean of its divisors is an integer number (70000).

2²⁶⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

265981 is a deficient number, since it is larger than the sum of its proper divisors (14019).

265981 is a wasteful number, since it uses less digits than its factorization.

265981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14018.

The product of its digits is 4320, while the sum is 31.

The square root of 265981 is about 515.7334582902. The cubic root of 265981 is about 64.3107446327.

The spelling of 265981 in words is "two hundred sixty-five thousand, nine hundred eighty-one".