91118389 has 2 divisors, whose sum is σ = 91118390. Its totient is φ = 91118388.

The previous prime is 91118371. The next prime is 91118399. The reversal of 91118389 is 98381119.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71537764 + 19580625 = 8458^2 + 4425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91118389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91118399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45559194 + 45559195.

It is an arithmetic number, because the mean of its divisors is an integer number (45559195).

Almost surely, 2^91118389 is an apocalyptic number.

It is an amenable number.

91118389 is a deficient number, since it is larger than the sum of its proper divisors (1).

91118389 is an equidigital number, since it uses as much as digits as its factorization.

91118389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 40.

The square root of 91118389 is about 9545.5952669281. The cubic root of 91118389 is about 449.9891174323.

The spelling of 91118389 in words is "ninety-one million, one hundred eighteen thousand, three hundred eighty-nine".