108820021 has 2 divisors, whose sum is σ = 108820022. Its totient is φ = 108820020.

The previous prime is 108820003. The next prime is 108820031. The reversal of 108820021 is 120028801.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107640625 + 1179396 = 10375^2 + 1086^2 .

It is an emirp because it is prime and its reverse (120028801) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-108820021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 108819974 and 108820001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (108820031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54410010 + 54410011.

It is an arithmetic number, because the mean of its divisors is an integer number (54410011).

Almost surely, 2^108820021 is an apocalyptic number.

It is an amenable number.

108820021 is a deficient number, since it is larger than the sum of its proper divisors (1).

108820021 is an equidigital number, since it uses as much as digits as its factorization.

108820021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 108820021 is about 10431.6835170551. The cubic root of 108820021 is about 477.4225577286.

Adding to 108820021 its reverse (120028801), we get a palindrome (228848822).

The spelling of 108820021 in words is "one hundred eight million, eight hundred twenty thousand, twenty-one".