998491001 has 2 divisors, whose sum is σ = 998491002. Its totient is φ = 998491000.

The previous prime is 998490979. The next prime is 998491027. The reversal of 998491001 is 100194899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 950118976 + 48372025 = 30824^2 + 6955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-998491001 is a prime.

It is equal to p_50774882 and since 998491001 and 50774882 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 998491001.

It is not a weakly prime, because it can be changed into another prime (998491031) 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, 499245500 + 499245501.

It is an arithmetic number, because the mean of its divisors is an integer number (499245501).

Almost surely, 2^998491001 is an apocalyptic number.

It is an amenable number.

998491001 is a deficient number, since it is larger than the sum of its proper divisors (1).

998491001 is an equidigital number, since it uses as much as digits as its factorization.

998491001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 998491001 is about 31598.9082248106. The cubic root of 998491001 is about 999.4967471123.

The spelling of 998491001 in words is "nine hundred ninety-eight million, four hundred ninety-one thousand, one".