99980000999981 has 2 divisors, whose sum is σ = 99980000999982. Its totient is φ = 99980000999980.

The previous prime is 99980000999947. The next prime is 99980001000007. The reversal of 99980000999981 is 18999900008999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64369732455625 + 35610268544356 = 8023075^2 + 5967434^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99980000999981 is a prime.

It is a super-2 number, since 2×99980000999981² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 99980000999896 and 99980000999905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99980000999911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49990000499990 + 49990000499991.

It is an arithmetic number, because the mean of its divisors is an integer number (49990000499991).

Almost surely, 2^{99980000999981} is an apocalyptic number.

It is an amenable number.

99980000999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

99980000999981 is an equidigital number, since it uses as much as digits as its factorization.

99980000999981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 306110016, while the sum is 80.

The spelling of 99980000999981 in words is "ninety-nine trillion, nine hundred eighty billion, nine hundred ninety-nine thousand, nine hundred eighty-one".