276821 has 2 divisors, whose sum is σ = 276822. Its totient is φ = 276820.

The previous prime is 276817. The next prime is 276823. The reversal of 276821 is 128672.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192721 + 84100 = 439^2 + 290^2 .

It is a cyclic number.

It is not a de Polignac number, because 276821 - 2² = 276817 is a prime.

It is a Sophie Germain prime.

Together with 276823, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a Curzon number.

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 276821.

It is not a weakly prime, because it can be changed into another prime (276823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 138410 + 138411.

It is an arithmetic number, because the mean of its divisors is an integer number (138411).

2²⁷⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

276821 is a deficient number, since it is larger than the sum of its proper divisors (1).

276821 is an equidigital number, since it uses as much as digits as its factorization.

276821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 26.

The square root of 276821 is about 526.1378146456. The cubic root of 276821 is about 65.1727946770.

The spelling of 276821 in words is "two hundred seventy-six thousand, eight hundred twenty-one".