99990181 has 2 divisors, whose sum is σ = 99990182. Its totient is φ = 99990180.

The previous prime is 99990161. The next prime is 99990239. The reversal of 99990181 is 18109999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98704225 + 1285956 = 9935^2 + 1134^2 .

It is an emirp because it is prime and its reverse (18109999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99990181 - 2⁷ = 99990053 is a prime.

It is a super-2 number, since 2×99990181² = 19996072592825522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99990161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49995090 + 49995091.

It is an arithmetic number, because the mean of its divisors is an integer number (49995091).

Almost surely, 2^99990181 is an apocalyptic number.

It is an amenable number.

99990181 is a deficient number, since it is larger than the sum of its proper divisors (1).

99990181 is an equidigital number, since it uses as much as digits as its factorization.

99990181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 99990181 is about 9999.5090379478. The cubic root of 99990181 is about 464.1436909438.

The spelling of 99990181 in words is "ninety-nine million, nine hundred ninety thousand, one hundred eighty-one".