8999000009981 has 2 divisors, whose sum is σ = 8999000009982. Its totient is φ = 8999000009980.

The previous prime is 8999000009953. The next prime is 8999000010031. The reversal of 8999000009981 is 1899000009998.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4724406544900 + 4274593465081 = 2173570^2 + 2067509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8999000009981 is a prime.

It is a super-2 number, since 2×8999000009981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8999000009921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4499500004990 + 4499500004991.

It is an arithmetic number, because the mean of its divisors is an integer number (4499500004991).

Almost surely, 2^{8999000009981} is an apocalyptic number.

It is an amenable number.

8999000009981 is a deficient number, since it is larger than the sum of its proper divisors (1).

8999000009981 is an equidigital number, since it uses as much as digits as its factorization.

8999000009981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3779136, while the sum is 62.

The spelling of 8999000009981 in words is "eight trillion, nine hundred ninety-nine billion, nine thousand, nine hundred eighty-one".