108821 has 2 divisors, whose sum is σ = 108822. Its totient is φ = 108820.

The previous prime is 108803. The next prime is 108827. The reversal of 108821 is 128801.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96721 + 12100 = 311^2 + 110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-108821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 108793 and 108802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (108827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54410 + 54411.

It is an arithmetic number, because the mean of its divisors is an integer number (54411).

2¹⁰⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

108821 is a deficient number, since it is larger than the sum of its proper divisors (1).

108821 is an equidigital number, since it uses as much as digits as its factorization.

108821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 108821 is about 329.8802813143. The cubic root of 108821 is about 47.7423989436.

Subtracting from 108821 its sum of digits (20), we obtain a palindrome (108801).

It can be divided in two parts, 108 and 821, that added together give a palindrome (929).

The spelling of 108821 in words is "one hundred eight thousand, eight hundred twenty-one".