9899999980 has 96 divisors (see below), whose sum is σ = 23741605440. Its totient is φ = 3435233280.

The previous prime is 9899999971. The next prime is 9899999987. The reversal of 9899999980 is 899999989.

It is a self number, because there is not a number n which added to its sum of digits gives 9899999980.

It is not an unprimeable number, because it can be changed into a prime (9899999987) 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, 4104975 + ... + 4107385.

It is an arithmetic number, because the mean of its divisors is an integer number (247308390).

Almost surely, 2^9899999980 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9899999980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11870802720).

9899999980 is an abundant number, since it is smaller than the sum of its proper divisors (13841605460).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9899999980 is a wasteful number, since it uses less digits than its factorization.

9899999980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3379 (or 3377 counting only the distinct ones).

The product of its (nonzero) digits is 306110016, while the sum is 79.

The square root of 9899999980 is about 99498.7436101582. The cubic root of 9899999980 is about 2147.2291675730.

The spelling of 9899999980 in words is "nine billion, eight hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty".