20816839 has 2 divisors, whose sum is σ = 20816840. Its totient is φ = 20816838.

The previous prime is 20816821. The next prime is 20816881. The reversal of 20816839 is 93861802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20816839 - 2¹¹ = 20814791 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20816798 and 20816807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20816819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10408419 + 10408420.

It is an arithmetic number, because the mean of its divisors is an integer number (10408420).

Almost surely, 2^20816839 is an apocalyptic number.

20816839 is a deficient number, since it is larger than the sum of its proper divisors (1).

20816839 is an equidigital number, since it uses as much as digits as its factorization.

20816839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 20816839 is about 4562.5474244111. The cubic root of 20816839 is about 275.0879674501.

The spelling of 20816839 in words is "twenty million, eight hundred sixteen thousand, eight hundred thirty-nine".