91001000999 has 2 divisors, whose sum is σ = 91001001000. Its totient is φ = 91001000998.

The previous prime is 91001000983. The next prime is 91001001019. The reversal of 91001000999 is 99900010019.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (99900010019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91001000999 - 2⁴ = 91001000983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91001008999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45500500499 + 45500500500.

It is an arithmetic number, because the mean of its divisors is an integer number (45500500500).

Almost surely, 2^91001000999 is an apocalyptic number.

91001000999 is a deficient number, since it is larger than the sum of its proper divisors (1).

91001000999 is an equidigital number, since it uses as much as digits as its factorization.

91001000999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6561, while the sum is 38.

The spelling of 91001000999 in words is "ninety-one billion, one million, nine hundred ninety-nine", and thus it is an aban number.