99980 has 12 divisors (see below), whose sum is σ = 210000. Its totient is φ = 39984.

The previous prime is 99971. The next prime is 99989. The reversal of 99980 is 8999.

It is an interprime number because it is at equal distance from previous prime (99971) and next prime (99989).

It is a plaindrome in base 13.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 99980.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99989) 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 3 ways as a sum of consecutive naturals, for example, 2480 + ... + 2519.

It is an arithmetic number, because the mean of its divisors is an integer number (17500).

2⁹⁹⁹⁸⁰ is an apocalyptic number.

It is an amenable number.

99980 is an abundant number, since it is smaller than the sum of its proper divisors (110020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105000).

99980 is a wasteful number, since it uses less digits than its factorization.

99980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5008 (or 5006 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 99980 is about 316.1961416589. The cubic root of 99980 is about 46.4127937373.

It can be divided in two parts, 99 and 980, that multiplied together give a triangular number (97020 = T₄₄₀).

The spelling of 99980 in words is "ninety-nine thousand, nine hundred eighty".