998822021 has 2 divisors, whose sum is σ = 998822022. Its totient is φ = 998822020.

The previous prime is 998821987. The next prime is 998822053. The reversal of 998822021 is 120228899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 963419521 + 35402500 = 31039^2 + 5950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-998822021 is a prime.

It is a Chen prime.

It is equal to p_50790947 and since 998822021 and 50790947 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 998822021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998822221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499411010 + 499411011.

It is an arithmetic number, because the mean of its divisors is an integer number (499411011).

Almost surely, 2^998822021 is an apocalyptic number.

It is an amenable number.

998822021 is a deficient number, since it is larger than the sum of its proper divisors (1).

998822021 is an equidigital number, since it uses as much as digits as its factorization.

998822021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 998822021 is about 31604.1456299644. The cubic root of 998822021 is about 999.6071860507.

The spelling of 998822021 in words is "nine hundred ninety-eight million, eight hundred twenty-two thousand, twenty-one".