19905139 has 2 divisors, whose sum is σ = 19905140. Its totient is φ = 19905138.

The previous prime is 19905133. The next prime is 19905161. The reversal of 19905139 is 93150991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19905139 - 2¹⁷ = 19774067 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19905098 and 19905107.

It is not a weakly prime, because it can be changed into another prime (19905133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9952569 + 9952570.

It is an arithmetic number, because the mean of its divisors is an integer number (9952570).

Almost surely, 2^19905139 is an apocalyptic number.

19905139 is a deficient number, since it is larger than the sum of its proper divisors (1).

19905139 is an equidigital number, since it uses as much as digits as its factorization.

19905139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10935, while the sum is 37.

The square root of 19905139 is about 4461.5175669272. The cubic root of 19905139 is about 271.0119274172.

The spelling of 19905139 in words is "nineteen million, nine hundred five thousand, one hundred thirty-nine".