989898787898861 has 2 divisors, whose sum is σ = 989898787898862. Its totient is φ = 989898787898860.

The previous prime is 989898787898833. The next prime is 989898787898869. The reversal of 989898787898861 is 168898787898989.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 692060879702500 + 297837908196361 = 26307050^2 + 17257981^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-989898787898861 is a prime.

It is a super-2 number, since 2×989898787898861² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989898787898869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494949393949430 + 494949393949431.

It is an arithmetic number, because the mean of its divisors is an integer number (494949393949431).

Almost surely, 2^{989898787898861} is an apocalyptic number.

It is an amenable number.

989898787898861 is a deficient number, since it is larger than the sum of its proper divisors (1).

989898787898861 is an equidigital number, since it uses as much as digits as its factorization.

989898787898861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4045267795968, while the sum is 113.

The spelling of 989898787898861 in words is "nine hundred eighty-nine trillion, eight hundred ninety-eight billion, seven hundred eighty-seven million, eight hundred ninety-eight thousand, eight hundred sixty-one".