9199991 has 2 divisors, whose sum is σ = 9199992. Its totient is φ = 9199990.

The previous prime is 9199987. The next prime is 9199997. The reversal of 9199991 is 1999919.

9199991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9199991 - 2² = 9199987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9199997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4599995 + 4599996.

It is an arithmetic number, because the mean of its divisors is an integer number (4599996).

Almost surely, 2^9199991 is an apocalyptic number.

9199991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9199991 is an equidigital number, since it uses as much as digits as its factorization.

9199991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 59049, while the sum is 47.

The square root of 9199991 is about 3033.1486940142. The cubic root of 9199991 is about 209.5378423067.

The spelling of 9199991 in words is "nine million, one hundred ninety-nine thousand, nine hundred ninety-one".