20439439 has 2 divisors, whose sum is σ = 20439440. Its totient is φ = 20439438.

The previous prime is 20439379. The next prime is 20439449. The reversal of 20439439 is 93493402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20439439 - 2¹³ = 20431247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20439449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10219719 + 10219720.

It is an arithmetic number, because the mean of its divisors is an integer number (10219720).

Almost surely, 2^20439439 is an apocalyptic number.

20439439 is a deficient number, since it is larger than the sum of its proper divisors (1).

20439439 is an equidigital number, since it uses as much as digits as its factorization.

20439439 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 34.

The square root of 20439439 is about 4520.9997788100. Note that the first 3 decimals coincide. The cubic root of 20439439 is about 273.4154114337.

The spelling of 20439439 in words is "twenty million, four hundred thirty-nine thousand, four hundred thirty-nine".