7878312289 has 4 divisors (see below), whose sum is σ = 8149978260. Its totient is φ = 7606646320.

The previous prime is 7878312287. The next prime is 7878312293. The reversal of 7878312289 is 9822138787.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9822138787 = 19 ⋅516954673.

It can be written as a sum of positive squares in 2 ways, for example, as 6582888225 + 1295424064 = 81135^2 + 35992^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878312289 - 2¹ = 7878312287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7878312287) 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, 135832942 + ... + 135832999.

It is an arithmetic number, because the mean of its divisors is an integer number (2037494565).

Almost surely, 2^7878312289 is an apocalyptic number.

It is an amenable number.

7878312289 is a deficient number, since it is larger than the sum of its proper divisors (271665971).

7878312289 is a wasteful number, since it uses less digits than its factorization.

7878312289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271665970.

The product of its digits is 2709504, while the sum is 55.

The square root of 7878312289 is about 88759.8574187679. The cubic root of 7878312289 is about 1989.8075021495.

The spelling of 7878312289 in words is "seven billion, eight hundred seventy-eight million, three hundred twelve thousand, two hundred eighty-nine".