26821 has 2 divisors, whose sum is σ = 26822. Its totient is φ = 26820.

The previous prime is 26813. The next prime is 26833. The reversal of 26821 is 12862.

It is a happy number.

26821 is nontrivially palindromic in base 12.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25921 + 900 = 161^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 26821 - 2³ = 26813 is a prime.

It is a Chen prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26801) by changing a digit.

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 as a sum of consecutive naturals, namely, 13410 + 13411.

It is an arithmetic number, because the mean of its divisors is an integer number (13411).

2²⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

26821 is a deficient number, since it is larger than the sum of its proper divisors (1).

26821 is an equidigital number, since it uses as much as digits as its factorization.

26821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 19.

The square root of 26821 is about 163.7711818361. The cubic root of 26821 is about 29.9335566551.

It can be divided in two parts, 268 and 21, that added together give a square (289 = 17²).

The spelling of 26821 in words is "twenty-six thousand, eight hundred twenty-one".