19638439 has 2 divisors, whose sum is σ = 19638440. Its totient is φ = 19638438.

The previous prime is 19638431. The next prime is 19638497. The reversal of 19638439 is 93483691.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19638439 - 2³ = 19638431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19638395 and 19638404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19638431) 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, 9819219 + 9819220.

It is an arithmetic number, because the mean of its divisors is an integer number (9819220).

Almost surely, 2^19638439 is an apocalyptic number.

19638439 is a deficient number, since it is larger than the sum of its proper divisors (1).

19638439 is an equidigital number, since it uses as much as digits as its factorization.

19638439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 43.

The square root of 19638439 is about 4431.5278403729. The cubic root of 19638439 is about 269.7960920436.

The spelling of 19638439 in words is "nineteen million, six hundred thirty-eight thousand, four hundred thirty-nine".