265821 has 4 divisors (see below), whose sum is σ = 354432. Its totient is φ = 177212.

The previous prime is 265819. The next prime is 265831. The reversal of 265821 is 128562.

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.

It is a cyclic number.

It is not a de Polignac number, because 265821 - 2¹ = 265819 is a prime.

It is a D-number.

It is a plaindrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 265791 and 265800.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 265821.

It is not an unprimeable number, because it can be changed into a prime (265831) 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, 44301 + ... + 44306.

It is an arithmetic number, because the mean of its divisors is an integer number (88608).

2²⁶⁵⁸²¹ is an apocalyptic number.

It is an amenable number.

265821 is a deficient number, since it is larger than the sum of its proper divisors (88611).

265821 is an equidigital number, since it uses as much as digits as its factorization.

265821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88610.

The product of its digits is 960, while the sum is 24.

The square root of 265821 is about 515.5783160685. The cubic root of 265821 is about 64.2978467401.

The spelling of 265821 in words is "two hundred sixty-five thousand, eight hundred twenty-one".