7987813 has 2 divisors, whose sum is σ = 7987814. Its totient is φ = 7987812.

The previous prime is 7987799. The next prime is 7987823. The reversal of 7987813 is 3187897.

7987813 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5373124 + 2614689 = 2318^2 + 1617^2 .

It is a cyclic number.

It is not a de Polignac number, because 7987813 - 2⁵ = 7987781 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 7987813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7987823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3993906 + 3993907.

It is an arithmetic number, because the mean of its divisors is an integer number (3993907).

Almost surely, 2^7987813 is an apocalyptic number.

It is an amenable number.

7987813 is a deficient number, since it is larger than the sum of its proper divisors (1).

7987813 is an equidigital number, since it uses as much as digits as its factorization.

7987813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 43.

The square root of 7987813 is about 2826.2719260538. The cubic root of 7987813 is about 199.8983900525.

The spelling of 7987813 in words is "seven million, nine hundred eighty-seven thousand, eight hundred thirteen".