19010809 has 2 divisors, whose sum is σ = 19010810. Its totient is φ = 19010808.

The previous prime is 19010791. The next prime is 19010867. The reversal of 19010809 is 90801091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17665209 + 1345600 = 4203^2 + 1160^2 .

It is an emirp because it is prime and its reverse (90801091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19010809 - 2⁹ = 19010297 is a prime.

It is a super-2 number, since 2×19010809² = 722821717668962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19010899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9505404 + 9505405.

It is an arithmetic number, because the mean of its divisors is an integer number (9505405).

Almost surely, 2^19010809 is an apocalyptic number.

It is an amenable number.

19010809 is a deficient number, since it is larger than the sum of its proper divisors (1).

19010809 is an equidigital number, since it uses as much as digits as its factorization.

19010809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 19010809 is about 4360.1386445846. The cubic root of 19010809 is about 266.8907566014.

The spelling of 19010809 in words is "nineteen million, ten thousand, eight hundred nine".