7798779818 has 16 divisors (see below), whose sum is σ = 12813412680. Its totient is φ = 3543461376.

The previous prime is 7798779811. The next prime is 7798779823. The reversal of 7798779818 is 8189778977.

It can be written as a sum of positive squares in 4 ways, for example, as 7714635889 + 84143929 = 87833^2 + 9173^2 .

It is a super-2 number, since 2×7798779818² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7798779811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3953771 + ... + 3955742.

Almost surely, 2^7798779818 is an apocalyptic number.

7798779818 is a deficient number, since it is larger than the sum of its proper divisors (5014632862).

7798779818 is a wasteful number, since it uses less digits than its factorization.

7798779818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7909561.

The product of its digits is 99574272, while the sum is 71.

The square root of 7798779818 is about 88310.7004728193. The cubic root of 7798779818 is about 1983.0890646482.

The spelling of 7798779818 in words is "seven billion, seven hundred ninety-eight million, seven hundred seventy-nine thousand, eight hundred eighteen".