9991254173 has 2 divisors, whose sum is σ = 9991254174. Its totient is φ = 9991254172.

The previous prime is 9991254167. The next prime is 9991254191. The reversal of 9991254173 is 3714521999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9408418009 + 582836164 = 96997^2 + 24142^2 .

It is a cyclic number.

It is not a de Polignac number, because 9991254173 - 2⁴ = 9991254157 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991254113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995627086 + 4995627087.

It is an arithmetic number, because the mean of its divisors is an integer number (4995627087).

Almost surely, 2^9991254173 is an apocalyptic number.

It is an amenable number.

9991254173 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991254173 is an equidigital number, since it uses as much as digits as its factorization.

9991254173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 612360, while the sum is 50.

The square root of 9991254173 is about 99956.2612996304. The cubic root of 9991254173 is about 2153.8064297383.

The spelling of 9991254173 in words is "nine billion, nine hundred ninety-one million, two hundred fifty-four thousand, one hundred seventy-three".