990999999097 has 2 divisors, whose sum is σ = 990999999098. Its totient is φ = 990999999096.

The previous prime is 990999999071. The next prime is 990999999103. The reversal of 990999999097 is 790999999099.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 758189889081 + 232810110016 = 870741^2 + 482504^2 .

It is an emirp because it is prime and its reverse (790999999099) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-990999999097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 990999998999 and 990999999017.

It is not a weakly prime, because it can be changed into another prime (990999999497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495499999548 + 495499999549.

It is an arithmetic number, because the mean of its divisors is an integer number (495499999549).

Almost surely, 2^990999999097 is an apocalyptic number.

It is an amenable number.

990999999097 is a deficient number, since it is larger than the sum of its proper divisors (1).

990999999097 is an equidigital number, since it uses as much as digits as its factorization.

990999999097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2711943423, while the sum is 88.

The spelling of 990999999097 in words is "nine hundred ninety billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, ninety-seven".