999999999878 has 32 divisors (see below), whose sum is σ = 1670514930720. Its totient is φ = 445092693760.

The previous prime is 999999999877. The next prime is 999999999899. The reversal of 999999999878 is 878999999999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999999999877) 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 15 ways as a sum of consecutive naturals, for example, 248975 + ... + 1435962.

It is an arithmetic number, because the mean of its divisors is an integer number (52203591585).

Almost surely, 2^999999999878 is an apocalyptic number.

999999999878 is a deficient number, since it is larger than the sum of its proper divisors (670514930842).

999999999878 is a wasteful number, since it uses less digits than its factorization.

999999999878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1685512.

The product of its digits is 173564379072, while the sum is 104.

The spelling of 999999999878 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred seventy-eight".