7878999990 has 128 divisors (see below), whose sum is σ = 20714618880. Its totient is φ = 1910563200.

The previous prime is 7878999943. The next prime is 7879000027. The reversal of 7878999990 is 999998787.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2242335 + ... + 2245845.

It is an arithmetic number, because the mean of its divisors is an integer number (161832960).

Almost surely, 2^7878999990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7878999990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10357309440).

7878999990 is an abundant number, since it is smaller than the sum of its proper divisors (12835618890).

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

7878999990 is a wasteful number, since it uses less digits than its factorization.

7878999990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3698.

The product of its (nonzero) digits is 185177664, while the sum is 75.

The square root of 7878999990 is about 88763.7312757863. The cubic root of 7878999990 is about 1989.8653974932.

The spelling of 7878999990 in words is "seven billion, eight hundred seventy-eight million, nine hundred ninety-nine thousand, nine hundred ninety".