3821 has 2 divisors, whose sum is σ = 3822. Its totient is φ = 3820.

The previous prime is 3803. The next prime is 3823. The reversal of 3821 is 1283.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3721 + 100 = 61^2 + 10^2 .

It is an emirp because it is prime and its reverse (1283) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3821 - 2¹⁰ = 2797 is a prime.

It is a Sophie Germain prime.

Together with 3823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 14.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 3796 and 3805.

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 3821.

It is not a weakly prime, because it can be changed into another prime (3823) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1910 + 1911.

It is an arithmetic number, because the mean of its divisors is an integer number (1911).

2³⁸²¹ is an apocalyptic number.

It is an amenable number.

3821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3821 is an equidigital number, since it uses as much as digits as its factorization.

3821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 14.

The square root of 3821 is about 61.8142378421. The cubic root of 3821 is about 15.6336005984.

Subtracting from 3821 its product of digits (48), we obtain a palindrome (3773).

It can be divided in two parts, 382 and 1, that added together give a palindrome (383).

The spelling of 3821 in words is "three thousand, eight hundred twenty-one".