91999423 has 4 divisors (see below), whose sum is σ = 92289960. Its totient is φ = 91708888.

The previous prime is 91999421. The next prime is 91999429. The reversal of 91999423 is 32499919.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91999423 - 2¹ = 91999421 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 (91999421) 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 in 3 ways as a sum of consecutive naturals, for example, 144793 + ... + 145426.

It is an arithmetic number, because the mean of its divisors is an integer number (23072490).

Almost surely, 2^91999423 is an apocalyptic number.

91999423 is a deficient number, since it is larger than the sum of its proper divisors (290537).

91999423 is a wasteful number, since it uses less digits than its factorization.

91999423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290536.

The product of its digits is 157464, while the sum is 46.

The square root of 91999423 is about 9591.6329683741. The cubic root of 91999423 is about 451.4347997830.

The spelling of 91999423 in words is "ninety-one million, nine hundred ninety-nine thousand, four hundred twenty-three".