7987713821 has 4 divisors (see below), whose sum is σ = 7998980700. Its totient is φ = 7976446944.

The previous prime is 7987713787. The next prime is 7987713827. The reversal of 7987713821 is 1283177897.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3047592025 + 4940121796 = 55205^2 + 70286^2 .

It is a cyclic number.

It is not a de Polignac number, because 7987713821 - 2¹⁸ = 7987451677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7987713827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5632376 + ... + 5633793.

It is an arithmetic number, because the mean of its divisors is an integer number (1999745175).

Almost surely, 2^7987713821 is an apocalyptic number.

It is an amenable number.

7987713821 is a deficient number, since it is larger than the sum of its proper divisors (11266879).

7987713821 is a wasteful number, since it uses less digits than its factorization.

7987713821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11266878.

The product of its digits is 1185408, while the sum is 53.

The square root of 7987713821 is about 89374.0108812400. The cubic root of 7987713821 is about 1998.9756271697.

The spelling of 7987713821 in words is "seven billion, nine hundred eighty-seven million, seven hundred thirteen thousand, eight hundred twenty-one".