99181 has 2 divisors, whose sum is σ = 99182. Its totient is φ = 99180.

The previous prime is 99173. The next prime is 99191. The reversal of 99181 is 18199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81225 + 17956 = 285^2 + 134^2 .

It is an emirp because it is prime and its reverse (18199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99181 - 2³ = 99173 is a prime.

It is a super-2 number, since 2×99181² = 19673741522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49590 + 49591.

It is an arithmetic number, because the mean of its divisors is an integer number (49591).

2⁹⁹¹⁸¹ is an apocalyptic number.

It is an amenable number.

99181 is a deficient number, since it is larger than the sum of its proper divisors (1).

99181 is an equidigital number, since it uses as much as digits as its factorization.

99181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 28.

The square root of 99181 is about 314.9301509859. The cubic root of 99181 is about 46.2888254454.

The spelling of 99181 in words is "ninety-nine thousand, one hundred eighty-one".