20128439 has 2 divisors, whose sum is σ = 20128440. Its totient is φ = 20128438.

The previous prime is 20128421. The next prime is 20128447. The reversal of 20128439 is 93482102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20128439 - 2²⁴ = 3351223 is a prime.

It is a Chen prime.

It is equal to p_1278254 and since 20128439 and 1278254 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20128469) 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, 10064219 + 10064220.

It is an arithmetic number, because the mean of its divisors is an integer number (10064220).

Almost surely, 2^20128439 is an apocalyptic number.

20128439 is a deficient number, since it is larger than the sum of its proper divisors (1).

20128439 is an equidigital number, since it uses as much as digits as its factorization.

20128439 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 20128439 is about 4486.4728908130. The cubic root of 20128439 is about 272.0215840355.

The spelling of 20128439 in words is "twenty million, one hundred twenty-eight thousand, four hundred thirty-nine".