275821 has 12 divisors (see below), whose sum is σ = 346332. Its totient is φ = 217728.

The previous prime is 275813. The next prime is 275827. The reversal of 275821 is 128572.

It can be written as a sum of positive squares in 2 ways, for example, as 35721 + 240100 = 189^2 + 490^2 .

It is not a de Polignac number, because 275821 - 2³ = 275813 is a prime.

275821 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (275827) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 421 + ... + 853.

It is an arithmetic number, because the mean of its divisors is an integer number (28861).

2²⁷⁵⁸²¹ is an apocalyptic number.

It is an amenable number.

275821 is a deficient number, since it is larger than the sum of its proper divisors (70511).

275821 is a wasteful number, since it uses less digits than its factorization.

275821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460 (or 453 counting only the distinct ones).

The product of its digits is 1120, while the sum is 25.

The square root of 275821 is about 525.1866334933. The cubic root of 275821 is about 65.0942223261.

The spelling of 275821 in words is "two hundred seventy-five thousand, eight hundred twenty-one".