19491890273 has 2 divisors, whose sum is σ = 19491890274. Its totient is φ = 19491890272.

The previous prime is 19491890161. The next prime is 19491890291. The reversal of 19491890273 is 37209819491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12370555729 + 7121334544 = 111223^2 + 84388^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19491890273 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19491893273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9745945136 + 9745945137.

It is an arithmetic number, because the mean of its divisors is an integer number (9745945137).

Almost surely, 2^19491890273 is an apocalyptic number.

It is an amenable number.

19491890273 is a deficient number, since it is larger than the sum of its proper divisors (1).

19491890273 is an equidigital number, since it uses as much as digits as its factorization.

19491890273 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 979776, while the sum is 53.

The spelling of 19491890273 in words is "nineteen billion, four hundred ninety-one million, eight hundred ninety thousand, two hundred seventy-three".