265840 has 20 divisors (see below), whose sum is σ = 618264. Its totient is φ = 106304.

The previous prime is 265831. The next prime is 265841. The reversal of 265840 is 48562.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (265841) by changing a digit.

265840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1582 + ... + 1741.

2²⁶⁵⁸⁴⁰ is an apocalyptic number.

265840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

265840 is an abundant number, since it is smaller than the sum of its proper divisors (352424).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

265840 is a wasteful number, since it uses less digits than its factorization.

265840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3336 (or 3330 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 265840 is about 515.5967416499. The cubic root of 265840 is about 64.2993786356.

The spelling of 265840 in words is "two hundred sixty-five thousand, eight hundred forty".