991163617 has 2 divisors, whose sum is σ = 991163618. Its totient is φ = 991163616.

The previous prime is 991163611. The next prime is 991163639. The reversal of 991163617 is 716361199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 978375841 + 12787776 = 31279^2 + 3576^2 .

It is a cyclic number.

It is not a de Polignac number, because 991163617 - 2⁷ = 991163489 is a prime.

It is not a weakly prime, because it can be changed into another prime (991163611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495581808 + 495581809.

It is an arithmetic number, because the mean of its divisors is an integer number (495581809).

Almost surely, 2^991163617 is an apocalyptic number.

It is an amenable number.

991163617 is a deficient number, since it is larger than the sum of its proper divisors (1).

991163617 is an equidigital number, since it uses as much as digits as its factorization.

991163617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 43.

The square root of 991163617 is about 31482.7511027864. The cubic root of 991163617 is about 997.0458204169.

The spelling of 991163617 in words is "nine hundred ninety-one million, one hundred sixty-three thousand, six hundred seventeen".