8991289 has 2 divisors, whose sum is σ = 8991290. Its totient is φ = 8991288.

The previous prime is 8991253. The next prime is 8991293. The reversal of 8991289 is 9821998.

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., 8880400 + 110889 = 2980^2 + 333^2 .

It is a cyclic number.

It is not a de Polignac number, because 8991289 - 2⁹ = 8990777 is a prime.

8991289 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (8991239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4495644 + 4495645.

It is an arithmetic number, because the mean of its divisors is an integer number (4495645).

Almost surely, 2^8991289 is an apocalyptic number.

It is an amenable number.

8991289 is a deficient number, since it is larger than the sum of its proper divisors (1).

8991289 is an equidigital number, since it uses as much as digits as its factorization.

8991289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 46.

The square root of 8991289 is about 2998.5478151932. The cubic root of 8991289 is about 207.9412509746.

It can be divided in two parts, 89 and 91289, that added together give a triangular number (91378 = T₄₂₇).

The spelling of 8991289 in words is "eight million, nine hundred ninety-one thousand, two hundred eighty-nine".