9978817 has 2 divisors, whose sum is σ = 9978818. Its totient is φ = 9978816.

The previous prime is 9978811. The next prime is 9978821. The reversal of 9978817 is 7188799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9709456 + 269361 = 3116^2 + 519^2 .

It is a cyclic number.

It is not a de Polignac number, because 9978817 - 2¹⁵ = 9946049 is a prime.

It is not a weakly prime, because it can be changed into another prime (9978811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989408 + 4989409.

It is an arithmetic number, because the mean of its divisors is an integer number (4989409).

Almost surely, 2^9978817 is an apocalyptic number.

It is an amenable number.

9978817 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978817 is an equidigital number, since it uses as much as digits as its factorization.

9978817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 49.

The square root of 9978817 is about 3158.9265581840. The cubic root of 9978817 is about 215.2912368279.

The spelling of 9978817 in words is "nine million, nine hundred seventy-eight thousand, eight hundred seventeen".