998888621 has 2 divisors, whose sum is σ = 998888622. Its totient is φ = 998888620.

The previous prime is 998888591. The next prime is 998888647. The reversal of 998888621 is 126888899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 845995396 + 152893225 = 29086^2 + 12365^2 .

It is an emirp because it is prime and its reverse (126888899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 998888621 - 2¹⁰ = 998887597 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998888521) 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, 499444310 + 499444311.

It is an arithmetic number, because the mean of its divisors is an integer number (499444311).

Almost surely, 2^998888621 is an apocalyptic number.

It is an amenable number.

998888621 is a deficient number, since it is larger than the sum of its proper divisors (1).

998888621 is an equidigital number, since it uses as much as digits as its factorization.

998888621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3981312, while the sum is 59.

The square root of 998888621 is about 31605.1992716388. The cubic root of 998888621 is about 999.6294030082.

The spelling of 998888621 in words is "nine hundred ninety-eight million, eight hundred eighty-eight thousand, six hundred twenty-one".