91199391 has 4 divisors (see below), whose sum is σ = 121599192. Its totient is φ = 60799592.

The previous prime is 91199389. The next prime is 91199419. The reversal of 91199391 is 19399119.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91199391 - 2¹ = 91199389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91199351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15199896 + ... + 15199901.

It is an arithmetic number, because the mean of its divisors is an integer number (30399798).

Almost surely, 2^91199391 is an apocalyptic number.

91199391 is a deficient number, since it is larger than the sum of its proper divisors (30399801).

91199391 is a wasteful number, since it uses less digits than its factorization.

91199391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30399800.

The product of its digits is 19683, while the sum is 42.

The square root of 91199391 is about 9549.8372237437. The cubic root of 91199391 is about 450.1224210137.

The spelling of 91199391 in words is "ninety-one million, one hundred ninety-nine thousand, three hundred ninety-one".