91989613 has 2 divisors, whose sum is σ = 91989614. Its totient is φ = 91989612.

The previous prime is 91989607. The next prime is 91989629. The reversal of 91989613 is 31698919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66618244 + 25371369 = 8162^2 + 5037^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91989613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91989643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45994806 + 45994807.

It is an arithmetic number, because the mean of its divisors is an integer number (45994807).

Almost surely, 2^91989613 is an apocalyptic number.

It is an amenable number.

91989613 is a deficient number, since it is larger than the sum of its proper divisors (1).

91989613 is an equidigital number, since it uses as much as digits as its factorization.

91989613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 104976, while the sum is 46.

The square root of 91989613 is about 9591.1215715369. The cubic root of 91989613 is about 451.4187535490.

The spelling of 91989613 in words is "ninety-one million, nine hundred eighty-nine thousand, six hundred thirteen".