9999872745778 has 8 divisors (see below), whose sum is σ = 14999825889072. Its totient is φ = 4999930782756.

The previous prime is 9999872745773. The next prime is 9999872745829. The reversal of 9999872745778 is 8775472789999.

9999872745778 is a nontrivial binomial coefficient, being equal to C(4472108, 2).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 9999872745692 and 9999872745701.

It is not an unprimeable number, because it can be changed into a prime (9999872745773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 4472107.

It is an arithmetic number, because the mean of its divisors is an integer number (1874978236134).

Almost surely, 2^{9999872745778} is an apocalyptic number.

9999872745778 is the 4472107-th triangular number and also the 2236054-th hexagonal number.

9999872745778 is the 1490703-rd centered nonagonal number.

9999872745778 is a deficient number, since it is larger than the sum of its proper divisors (4999953143294).

9999872745778 is a wasteful number, since it uses less digits than its factorization.

9999872745778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5590136.

The product of its digits is 40327580160, while the sum is 91.

The spelling of 9999872745778 in words is "nine trillion, nine hundred ninety-nine billion, eight hundred seventy-two million, seven hundred forty-five thousand, seven hundred seventy-eight".