9978649 has 2 divisors, whose sum is σ = 9978650. Its totient is φ = 9978648.

The previous prime is 9978637. The next prime is 9978653. The reversal of 9978649 is 9468799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6215049 + 3763600 = 2493^2 + 1940^2 .

It is a cyclic number.

It is not a de Polignac number, because 9978649 - 2¹⁷ = 9847577 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 9978596 and 9978605.

It is not a weakly prime, because it can be changed into another prime (9978659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989324 + 4989325.

It is an arithmetic number, because the mean of its divisors is an integer number (4989325).

Almost surely, 2^9978649 is an apocalyptic number.

It is an amenable number.

9978649 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978649 is an equidigital number, since it uses as much as digits as its factorization.

9978649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 52.

The square root of 9978649 is about 3158.8999667606. The cubic root of 9978649 is about 215.2900286309.

The spelling of 9978649 in words is "nine million, nine hundred seventy-eight thousand, six hundred forty-nine".