9919979 has 2 divisors, whose sum is σ = 9919980. Its totient is φ = 9919978.

The previous prime is 9919963. The next prime is 9919997. The reversal of 9919979 is 9799199.

Together with next prime (9919997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9919979 - 2⁴ = 9919963 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9919979.

It is not a weakly prime, because it can be changed into another prime (9919939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4959989 + 4959990.

It is an arithmetic number, because the mean of its divisors is an integer number (4959990).

Almost surely, 2^9919979 is an apocalyptic number.

9919979 is a deficient number, since it is larger than the sum of its proper divisors (1).

9919979 is an equidigital number, since it uses as much as digits as its factorization.

9919979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 413343, while the sum is 53.

The square root of 9919979 is about 3149.5998158496. The cubic root of 9919979 is about 214.8672625775.

The spelling of 9919979 in words is "nine million, nine hundred nineteen thousand, nine hundred seventy-nine".