990811121 has 2 divisors, whose sum is σ = 990811122. Its totient is φ = 990811120.

The previous prime is 990811109. The next prime is 990811139. The reversal of 990811121 is 121118099.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 989731600 + 1079521 = 31460^2 + 1039^2 .

It is an emirp because it is prime and its reverse (121118099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 990811121 - 2¹⁰ = 990810097 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (920811121) 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, 495405560 + 495405561.

It is an arithmetic number, because the mean of its divisors is an integer number (495405561).

Almost surely, 2^990811121 is an apocalyptic number.

It is an amenable number.

990811121 is a deficient number, since it is larger than the sum of its proper divisors (1).

990811121 is an equidigital number, since it uses as much as digits as its factorization.

990811121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 32.

The square root of 990811121 is about 31477.1523648503. The cubic root of 990811121 is about 996.9276104230.

The spelling of 990811121 in words is "nine hundred ninety million, eight hundred eleven thousand, one hundred twenty-one".