99691 has 4 divisors (see below), whose sum is σ = 100584. Its totient is φ = 98800.

The previous prime is 99689. The next prime is 99707. The reversal of 99691 is 19699.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 99691 - 2¹ = 99689 is a prime.

It is a Duffinian number.

99691 is a lucky number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (99611) 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, 250 + ... + 511.

It is an arithmetic number, because the mean of its divisors is an integer number (25146).

2⁹⁹⁶⁹¹ is an apocalyptic number.

99691 is a deficient number, since it is larger than the sum of its proper divisors (893).

99691 is a wasteful number, since it uses less digits than its factorization.

99691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892.

The product of its digits is 4374, while the sum is 34.

The square root of 99691 is about 315.7388161123. The cubic root of 99691 is about 46.3680306438.

The spelling of 99691 in words is "ninety-nine thousand, six hundred ninety-one".