91990559 has 4 divisors (see below), whose sum is σ = 92599920. Its totient is φ = 91381200.

The previous prime is 91990543. The next prime is 91990579. The reversal of 91990559 is 95509919.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95509919 = 829 ⋅115211.

It is a cyclic number.

It is not a de Polignac number, because 91990559 - 2⁴ = 91990543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91990579) 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 in 3 ways as a sum of consecutive naturals, for example, 304454 + ... + 304755.

It is an arithmetic number, because the mean of its divisors is an integer number (23149980).

Almost surely, 2^91990559 is an apocalyptic number.

91990559 is a deficient number, since it is larger than the sum of its proper divisors (609361).

91990559 is a wasteful number, since it uses less digits than its factorization.

91990559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609360.

The product of its (nonzero) digits is 164025, while the sum is 47.

The square root of 91990559 is about 9591.1708878531. The cubic root of 91990559 is about 451.4203009726.

The spelling of 91990559 in words is "ninety-one million, nine hundred ninety thousand, five hundred fifty-nine".