21108163 has 2 divisors, whose sum is σ = 21108164. Its totient is φ = 21108162.

The previous prime is 21108137. The next prime is 21108173. The reversal of 21108163 is 36180112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21108163 - 2¹⁷ = 20977091 is a prime.

It is not a weakly prime, because it can be changed into another prime (21108103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10554081 + 10554082.

It is an arithmetic number, because the mean of its divisors is an integer number (10554082).

Almost surely, 2^21108163 is an apocalyptic number.

21108163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21108163 is an equidigital number, since it uses as much as digits as its factorization.

21108163 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 21108163 is about 4594.3620884732. The cubic root of 21108163 is about 276.3652789692.

Adding to 21108163 its reverse (36180112), we get a palindrome (57288275).

The spelling of 21108163 in words is "twenty-one million, one hundred eight thousand, one hundred sixty-three".