9978961 has 2 divisors, whose sum is σ = 9978962. Its totient is φ = 9978960.

The previous prime is 9978959. The next prime is 9978989. The reversal of 9978961 is 1698799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8088336 + 1890625 = 2844^2 + 1375^2 .

It is an emirp because it is prime and its reverse (1698799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9978961 - 2¹ = 9978959 is a prime.

Together with 9978959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (9978911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989480 + 4989481.

It is an arithmetic number, because the mean of its divisors is an integer number (4989481).

Almost surely, 2^9978961 is an apocalyptic number.

It is an amenable number.

9978961 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978961 is an equidigital number, since it uses as much as digits as its factorization.

9978961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 49.

The square root of 9978961 is about 3158.9493506544. The cubic root of 9978961 is about 215.2922724146.

The spelling of 9978961 in words is "nine million, nine hundred seventy-eight thousand, nine hundred sixty-one".