9909999878 has 8 divisors (see below), whose sum is σ = 14868304272. Its totient is φ = 4953898456.

The previous prime is 9909999877. The next prime is 9909999881. The reversal of 9909999878 is 8789999099.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 9909999799 and 9909999808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9909999871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 539450 + ... + 557517.

It is an arithmetic number, because the mean of its divisors is an integer number (1858538034).

Almost surely, 2^9909999878 is an apocalyptic number.

9909999878 is a deficient number, since it is larger than the sum of its proper divisors (4958304394).

9909999878 is a wasteful number, since it uses less digits than its factorization.

9909999878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1101486.

The product of its (nonzero) digits is 238085568, while the sum is 77.

The square root of 9909999878 is about 99548.9823051949. The cubic root of 9909999878 is about 2147.9518897001.

The spelling of 9909999878 in words is "nine billion, nine hundred nine million, nine hundred ninety-nine thousand, eight hundred seventy-eight".