989942981 has 2 divisors, whose sum is σ = 989942982. Its totient is φ = 989942980.

The previous prime is 989942971. The next prime is 989943001. The reversal of 989942981 is 189249989.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 708038881 + 281904100 = 26609^2 + 16790^2 .

It is an emirp because it is prime and its reverse (189249989) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-989942981 is a prime.

It is a super-2 number, since 2×989942981² = 1959974211262332722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 989942981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989942971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494971490 + 494971491.

It is an arithmetic number, because the mean of its divisors is an integer number (494971491).

Almost surely, 2^989942981 is an apocalyptic number.

It is an amenable number.

989942981 is a deficient number, since it is larger than the sum of its proper divisors (1).

989942981 is an equidigital number, since it uses as much as digits as its factorization.

989942981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 59.

The square root of 989942981 is about 31463.3593406680. The cubic root of 989942981 is about 996.6363589376.

The spelling of 989942981 in words is "nine hundred eighty-nine million, nine hundred forty-two thousand, nine hundred eighty-one".