998966555981 has 16 divisors (see below), whose sum is σ = 1010681867520. Its totient is φ = 987291782400.

The previous prime is 998966555971. The next prime is 998966555989. The reversal of 998966555981 is 189555669899.

It is a cyclic number.

It is not a de Polignac number, because 998966555981 - 2³⁰ = 997892814157 is a prime.

It is a super-2 number, since 2×998966555981² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 998966555896 and 998966555905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998966555989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 188374976 + ... + 188380278.

It is an arithmetic number, because the mean of its divisors is an integer number (63167616720).

Almost surely, 2^998966555981 is an apocalyptic number.

It is an amenable number.

998966555981 is a deficient number, since it is larger than the sum of its proper divisors (11715311539).

998966555981 is a wasteful number, since it uses less digits than its factorization.

998966555981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8716.

The product of its digits is 1889568000, while the sum is 80.

The spelling of 998966555981 in words is "nine hundred ninety-eight billion, nine hundred sixty-six million, five hundred fifty-five thousand, nine hundred eighty-one".