989898787898791 has 2 divisors, whose sum is σ = 989898787898792. Its totient is φ = 989898787898790.

The previous prime is 989898787898789. The next prime is 989898787898833. The reversal of 989898787898791 is 197898787898989.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 989898787898791 - 2¹ = 989898787898789 is a prime.

It is a super-2 number, since 2×989898787898791² (a number of 31 digits) contains 22 as substring.

Together with 989898787898789, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989898787896791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494949393949395 + 494949393949396.

It is an arithmetic number, because the mean of its divisors is an integer number (494949393949396).

Almost surely, 2^{989898787898791} is an apocalyptic number.

989898787898791 is a deficient number, since it is larger than the sum of its proper divisors (1).

989898787898791 is an equidigital number, since it uses as much as digits as its factorization.

989898787898791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5309413982208, while the sum is 115.

The spelling of 989898787898791 in words is "nine hundred eighty-nine trillion, eight hundred ninety-eight billion, seven hundred eighty-seven million, eight hundred ninety-eight thousand, seven hundred ninety-one".