91699999 has 4 divisors (see below), whose sum is σ = 91726560. Its totient is φ = 91673440.

The previous prime is 91699981. The next prime is 91700009. The reversal of 91699999 is 99999619.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99999619 = 2381 ⋅41999.

It is a cyclic number.

It is not a de Polignac number, because 91699999 - 2¹³ = 91691807 is a prime.

It is a Duffinian number.

91699999 is a modest number, since divided by 9999 gives 9169 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91699939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7162 + ... + 15319.

It is an arithmetic number, because the mean of its divisors is an integer number (22931640).

Almost surely, 2^91699999 is an apocalyptic number.

91699999 is a deficient number, since it is larger than the sum of its proper divisors (26561).

91699999 is a wasteful number, since it uses less digits than its factorization.

91699999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26560.

The product of its digits is 3188646, while the sum is 61.

The square root of 91699999 is about 9576.0116436855. The cubic root of 91699999 is about 450.9445165545.

The spelling of 91699999 in words is "ninety-one million, six hundred ninety-nine thousand, nine hundred ninety-nine".