7878479991 has 16 divisors (see below), whose sum is σ = 10610885376. Its totient is φ = 5199238656.

The previous prime is 7878479989. The next prime is 7878480013. The reversal of 7878479991 is 1999748787.

It is not a de Polignac number, because 7878479991 - 2¹ = 7878479989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7878479911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1320471 + ... + 1326423.

It is an arithmetic number, because the mean of its divisors is an integer number (663180336).

Almost surely, 2^7878479991 is an apocalyptic number.

7878479991 is a deficient number, since it is larger than the sum of its proper divisors (2732405385).

7878479991 is a wasteful number, since it uses less digits than its factorization.

7878479991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10342.

The product of its digits is 64012032, while the sum is 69.

The square root of 7878479991 is about 88760.8021088138. The cubic root of 7878479991 is about 1989.8216207541.

The spelling of 7878479991 in words is "seven billion, eight hundred seventy-eight million, four hundred seventy-nine thousand, nine hundred ninety-one".