19909139 has 2 divisors, whose sum is σ = 19909140. Its totient is φ = 19909138.

The previous prime is 19909121. The next prime is 19909157. The reversal of 19909139 is 93190991.

It is a balanced prime because it is at equal distance from previous prime (19909121) and next prime (19909157).

It is a cyclic number.

It is not a de Polignac number, because 19909139 - 2⁸ = 19908883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19909096 and 19909105.

It is not a weakly prime, because it can be changed into another prime (19909639) 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, 9954569 + 9954570.

It is an arithmetic number, because the mean of its divisors is an integer number (9954570).

Almost surely, 2^19909139 is an apocalyptic number.

19909139 is a deficient number, since it is larger than the sum of its proper divisors (1).

19909139 is an equidigital number, since it uses as much as digits as its factorization.

19909139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19683, while the sum is 41.

The square root of 19909139 is about 4461.9658223702. The cubic root of 19909139 is about 271.0300797664.

The spelling of 19909139 in words is "nineteen million, nine hundred nine thousand, one hundred thirty-nine".