99681 has 8 divisors (see below), whose sum is σ = 134400.
Its totient is φ = 65712.
The previous prime is 99679. The next prime is 99689. The reversal of 99681 is 18699.
It can be divided in two parts, 99 and 681, that added together give a triangular number (780 = T39).
It is a happy number.
99681 is a nontrivial binomial coefficient, being equal to C(447, 2).
It is a sphenic number, since it is the product of 3 distinct primes.
It is not a de Polignac number, because 99681 - 21 = 99679 is a prime.
It is a super-2 number, since 2×996812 = 19872603522, which contains 22 as substring.
It is not an unprimeable number, because it can be changed into a prime (99689) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 336 + ... + 558.
It is an arithmetic number, because the mean of its divisors is an integer number (16800).
299681 is an apocalyptic number.
99681 is the 446-th triangular number.
It is an amenable number.
99681 is a deficient number, since it is larger than the sum of its proper divisors (34719).
99681 is a wasteful number, since it uses less digits than its factorization.
99681 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 375.
The product of its digits is 3888, while the sum is 33.
The square root of 99681 is about 315.7229798415.
The cubic root of 99681 is about 46.3664802002.
The spelling of 99681 in words is "ninety-nine thousand, six hundred eighty-one".