20490839 has 2 divisors, whose sum is σ = 20490840. Its totient is φ = 20490838.

The previous prime is 20490823. The next prime is 20490917. The reversal of 20490839 is 93809402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20490839 - 2⁴ = 20490823 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20490799 and 20490808.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20490439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10245419 + 10245420.

It is an arithmetic number, because the mean of its divisors is an integer number (10245420).

Almost surely, 2^20490839 is an apocalyptic number.

20490839 is a deficient number, since it is larger than the sum of its proper divisors (1).

20490839 is an equidigital number, since it uses as much as digits as its factorization.

20490839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20490839 is about 4526.6807928106. The cubic root of 20490839 is about 273.6444096987.

The spelling of 20490839 in words is "twenty million, four hundred ninety thousand, eight hundred thirty-nine".