998185621 has 2 divisors, whose sum is σ = 998185622. Its totient is φ = 998185620.

The previous prime is 998185589. The next prime is 998185627. The reversal of 998185621 is 126581899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 902341521 + 95844100 = 30039^2 + 9790^2 .

It is a cyclic number.

It is not a de Polignac number, because 998185621 - 2⁵ = 998185589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998185627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499092810 + 499092811.

It is an arithmetic number, because the mean of its divisors is an integer number (499092811).

Almost surely, 2^998185621 is an apocalyptic number.

It is an amenable number.

998185621 is a deficient number, since it is larger than the sum of its proper divisors (1).

998185621 is an equidigital number, since it uses as much as digits as its factorization.

998185621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 49.

The square root of 998185621 is about 31594.0757263130. The cubic root of 998185621 is about 999.3948408563.

The spelling of 998185621 in words is "nine hundred ninety-eight million, one hundred eighty-five thousand, six hundred twenty-one".