99869981 has 2 divisors, whose sum is σ = 99869982. Its totient is φ = 99869980.

The previous prime is 99869977. The next prime is 99869989. The reversal of 99869981 is 18996899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72097081 + 27772900 = 8491^2 + 5270^2 .

It is a cyclic number.

It is not a de Polignac number, because 99869981 - 2² = 99869977 is a prime.

It is a super-2 number, since 2×99869981² = 19948026209880722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99869981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99869989) 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, 49934990 + 49934991.

It is an arithmetic number, because the mean of its divisors is an integer number (49934991).

Almost surely, 2^99869981 is an apocalyptic number.

It is an amenable number.

99869981 is a deficient number, since it is larger than the sum of its proper divisors (1).

99869981 is an equidigital number, since it uses as much as digits as its factorization.

99869981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2519424, while the sum is 59.

The square root of 99869981 is about 9993.4969355076. The cubic root of 99869981 is about 463.9576312012.

The spelling of 99869981 in words is "ninety-nine million, eight hundred sixty-nine thousand, nine hundred eighty-one".