99881 has 2 divisors, whose sum is σ = 99882. Its totient is φ = 99880.

The previous prime is 99877. The next prime is 99901. The reversal of 99881 is 18899.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99856 + 25 = 316^2 + 5^2 .

It is an emirp because it is prime and its reverse (18899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99881 - 2² = 99877 is a prime.

It is a super-2 number, since 2×99881² = 19952428322, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99871) 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 as a sum of consecutive naturals, namely, 49940 + 49941.

It is an arithmetic number, because the mean of its divisors is an integer number (49941).

2⁹⁹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

99881 is a deficient number, since it is larger than the sum of its proper divisors (1).

99881 is an equidigital number, since it uses as much as digits as its factorization.

99881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 35.

The square root of 99881 is about 316.0395544865. The cubic root of 99881 is about 46.3974693923.

The spelling of 99881 in words is "ninety-nine thousand, eight hundred eighty-one".