9999999872 has 16 divisors (see below), whose sum is σ = 19921875000. Its totient is φ = 4999999872.

The previous prime is 9999999851. The next prime is 9999999881. The reversal of 9999999872 is 2789999999.

It is a tau number, because it is divible by the number of its divisors (16).

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39062372 + ... + 39062627.

Almost surely, 2^9999999872 is an apocalyptic number.

It is an amenable number.

9999999872 is a deficient number, since it is larger than the sum of its proper divisors (9921875128).

9999999872 is an equidigital number, since it uses as much as digits as its factorization.

9999999872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78125013 (or 78125001 counting only the distinct ones).

The product of its digits is 535692528, while the sum is 80.

The square root of 9999999872 is about 99999.9993600000. Note that the first 3 decimals coincide. The cubic root of 9999999872 is about 2154.4346808396.

The spelling of 9999999872 in words is "nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred seventy-two".