9978919 has 2 divisors, whose sum is σ = 9978920. Its totient is φ = 9978918.

The previous prime is 9978911. The next prime is 9978959. The reversal of 9978919 is 9198799.

It is a weak prime.

It is an emirp because it is prime and its reverse (9198799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9978919 - 2³ = 9978911 is a prime.

It is a super-2 number, since 2×9978919² = 199157648817122, which contains 22 as substring.

It is a congruent number.

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, 4989459 + 4989460.

It is an arithmetic number, because the mean of its divisors is an integer number (4989460).

Almost surely, 2^9978919 is an apocalyptic number.

9978919 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978919 is an equidigital number, since it uses as much as digits as its factorization.

9978919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 52.

The square root of 9978919 is about 3158.9427028675. The cubic root of 9978919 is about 215.2919703695.

The spelling of 9978919 in words is "nine million, nine hundred seventy-eight thousand, nine hundred nineteen".