989929981 has 2 divisors, whose sum is σ = 989929982. Its totient is φ = 989929980.

The previous prime is 989929939. The next prime is 989929999. The reversal of 989929981 is 189929989.

989929981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 509224356 + 480705625 = 22566^2 + 21925^2 .

It is a cyclic number.

It is not a de Polignac number, because 989929981 - 2¹³ = 989921789 is a prime.

It is a super-2 number, since 2×989929981² = 1959922734565320722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989929901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494964990 + 494964991.

It is an arithmetic number, because the mean of its divisors is an integer number (494964991).

Almost surely, 2^989929981 is an apocalyptic number.

It is an amenable number.

989929981 is a deficient number, since it is larger than the sum of its proper divisors (1).

989929981 is an equidigital number, since it uses as much as digits as its factorization.

989929981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7558272, while the sum is 64.

The square root of 989929981 is about 31463.1527504794. The cubic root of 989929981 is about 996.6319962859.

The spelling of 989929981 in words is "nine hundred eighty-nine million, nine hundred twenty-nine thousand, nine hundred eighty-one".