9191561 has 2 divisors, whose sum is σ = 9191562. Its totient is φ = 9191560.

The previous prime is 9191549. The next prime is 9191563. The reversal of 9191561 is 1651919.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8231161 + 960400 = 2869^2 + 980^2 .

It is a cyclic number.

It is not a de Polignac number, because 9191561 - 2¹⁰ = 9190537 is a prime.

Together with 9191563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9191563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4595780 + 4595781.

It is an arithmetic number, because the mean of its divisors is an integer number (4595781).

Almost surely, 2^9191561 is an apocalyptic number.

It is an amenable number.

9191561 is a deficient number, since it is larger than the sum of its proper divisors (1).

9191561 is an equidigital number, since it uses as much as digits as its factorization.

9191561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2430, while the sum is 32.

The square root of 9191561 is about 3031.7587305061. The cubic root of 9191561 is about 209.4738225409.

The spelling of 9191561 in words is "nine million, one hundred ninety-one thousand, five hundred sixty-one".