998218793881 has 9 divisors (see below), whose sum is σ = 1006268584149. Its totient is φ = 990232915644.

The previous prime is 998218793863. The next prime is 998218793893. The reversal of 998218793881 is 188397812899.

It is a happy number.

The square root of 998218793881 is 999109.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 998218793881 - 2⁷ = 998218793753 is a prime.

It is a super-2 number, since 2×998218793881² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (998218793821) 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 in 8 ways as a sum of consecutive naturals, for example, 126882910 + ... + 126890776.

It is an arithmetic number, because the mean of its divisors is an integer number (111807620461).

Almost surely, 2^998218793881 is an apocalyptic number.

998218793881 is the 999109-th square number.

998218793881 is the 499555-th centered octagonal number.

It is an amenable number.

998218793881 is a deficient number, since it is larger than the sum of its proper divisors (8049790268).

998218793881 is an frugal number, since it uses more digits than its factorization.

998218793881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15988 (or 7994 counting only the distinct ones).

The product of its digits is 125411328, while the sum is 73.

The spelling of 998218793881 in words is "nine hundred ninety-eight billion, two hundred eighteen million, seven hundred ninety-three thousand, eight hundred eighty-one".