91000999 has 2 divisors, whose sum is σ = 91001000. Its totient is φ = 91000998.

The previous prime is 91000981. The next prime is 91001059. The reversal of 91000999 is 99900019.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91000999 - 2¹¹ = 90998951 is a prime.

91000999 is a modest number, since divided by 999 gives 91 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91000919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45500499 + 45500500.

It is an arithmetic number, because the mean of its divisors is an integer number (45500500).

Almost surely, 2^91000999 is an apocalyptic number.

91000999 is a deficient number, since it is larger than the sum of its proper divisors (1).

91000999 is an equidigital number, since it uses as much as digits as its factorization.

91000999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 91000999 is about 9539.4443758533. Note that the first 3 decimals coincide. The cubic root of 91000999 is about 449.7957904715.

The spelling of 91000999 in words is "ninety-one million, nine hundred ninety-nine", and thus it is an aban number.