91139999 has 2 divisors, whose sum is σ = 91140000. Its totient is φ = 91139998.

The previous prime is 91139981. The next prime is 91140061. The reversal of 91139999 is 99993119.

It is a weak prime.

It is an emirp because it is prime and its reverse (99993119) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91139999 - 2⁸ = 91139743 is a prime.

It is a Chen prime.

91139999 is a modest number, since divided by 9999 gives 9113 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91139929) 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 as a sum of consecutive naturals, namely, 45569999 + 45570000.

It is an arithmetic number, because the mean of its divisors is an integer number (45570000).

Almost surely, 2^91139999 is an apocalyptic number.

91139999 is a deficient number, since it is larger than the sum of its proper divisors (1).

91139999 is an equidigital number, since it uses as much as digits as its factorization.

91139999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 177147, while the sum is 50.

The square root of 91139999 is about 9546.7271355161. The cubic root of 91139999 is about 450.0246883574.

The spelling of 91139999 in words is "ninety-one million, one hundred thirty-nine thousand, nine hundred ninety-nine".