989865997 has 2 divisors, whose sum is σ = 989865998. Its totient is φ = 989865996.

The previous prime is 989865979. The next prime is 989866027. The reversal of 989865997 is 799568989.

Together with previous prime (989865979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 545035716 + 444830281 = 23346^2 + 21091^2 .

It is an emirp because it is prime and its reverse (799568989) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 989865997 - 2⁷ = 989865869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989865907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494932998 + 494932999.

It is an arithmetic number, because the mean of its divisors is an integer number (494932999).

Almost surely, 2^989865997 is an apocalyptic number.

It is an amenable number.

989865997 is a deficient number, since it is larger than the sum of its proper divisors (1).

989865997 is an equidigital number, since it uses as much as digits as its factorization.

989865997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 88179840, while the sum is 70.

The square root of 989865997 is about 31462.1359255852. The cubic root of 989865997 is about 996.6105234286.

The spelling of 989865997 in words is "nine hundred eighty-nine million, eight hundred sixty-five thousand, nine hundred ninety-seven".