91988669 has 2 divisors, whose sum is σ = 91988670. Its totient is φ = 91988668.

The previous prime is 91988647. The next prime is 91988681. The reversal of 91988669 is 96688919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80766169 + 11222500 = 8987^2 + 3350^2 .

It is a cyclic number.

It is not a de Polignac number, because 91988669 - 2²⁰ = 90940093 is a prime.

It is a super-2 number, since 2×91988669² = 16923830448783122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91988639) 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, 45994334 + 45994335.

It is an arithmetic number, because the mean of its divisors is an integer number (45994335).

Almost surely, 2^91988669 is an apocalyptic number.

It is an amenable number.

91988669 is a deficient number, since it is larger than the sum of its proper divisors (1).

91988669 is an equidigital number, since it uses as much as digits as its factorization.

91988669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1679616, while the sum is 56.

The square root of 91988669 is about 9591.0723592307. The cubic root of 91988669 is about 451.4172093864.

The spelling of 91988669 in words is "ninety-one million, nine hundred eighty-eight thousand, six hundred sixty-nine".