9899999979 has 32 divisors (see below), whose sum is σ = 13712219136. Its totient is φ = 6348424320.

The previous prime is 9899999971. The next prime is 9899999987. The reversal of 9899999979 is 9799999989.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (9899999971) and next prime (9899999987).

It is not a de Polignac number, because 9899999979 - 2³ = 9899999971 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 9899999895 and 9899999904.

It is not an unprimeable number, because it can be changed into a prime (9899999971) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3650434 + ... + 3653144.

It is an arithmetic number, because the mean of its divisors is an integer number (428506848).

Almost surely, 2^9899999979 is an apocalyptic number.

9899999979 is a deficient number, since it is larger than the sum of its proper divisors (3812219157).

9899999979 is a wasteful number, since it uses less digits than its factorization.

9899999979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3115.

The product of its digits is 2410616376, while the sum is 87.

The square root of 9899999979 is about 99498.7436051330. The cubic root of 9899999979 is about 2147.2291675007.

The spelling of 9899999979 in words is "nine billion, eight hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred seventy-nine".