998603561 has 2 divisors, whose sum is σ = 998603562. Its totient is φ = 998603560.

The previous prime is 998603533. The next prime is 998603623. The reversal of 998603561 is 165306899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 907515625 + 91087936 = 30125^2 + 9544^2 .

It is an emirp because it is prime and its reverse (165306899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 998603561 - 2¹⁸ = 998341417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (998603521) 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, 499301780 + 499301781.

It is an arithmetic number, because the mean of its divisors is an integer number (499301781).

Almost surely, 2^998603561 is an apocalyptic number.

It is an amenable number.

998603561 is a deficient number, since it is larger than the sum of its proper divisors (1).

998603561 is an equidigital number, since it uses as much as digits as its factorization.

998603561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 998603561 is about 31600.6892488123. The cubic root of 998603561 is about 999.5343034938.

The spelling of 998603561 in words is "nine hundred ninety-eight million, six hundred three thousand, five hundred sixty-one".