7987523821 has 2 divisors, whose sum is σ = 7987523822. Its totient is φ = 7987523820.

The previous prime is 7987523801. The next prime is 7987523833. The reversal of 7987523821 is 1283257897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6031230921 + 1956292900 = 77661^2 + 44230^2 .

It is a cyclic number.

It is not a de Polignac number, because 7987523821 - 2¹³ = 7987515629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7987523801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3993761910 + 3993761911.

It is an arithmetic number, because the mean of its divisors is an integer number (3993761911).

Almost surely, 2^7987523821 is an apocalyptic number.

It is an amenable number.

7987523821 is a deficient number, since it is larger than the sum of its proper divisors (1).

7987523821 is an equidigital number, since it uses as much as digits as its factorization.

7987523821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1693440, while the sum is 52.

The square root of 7987523821 is about 89372.9479260923. The cubic root of 7987523821 is about 1998.9597774790.

The spelling of 7987523821 in words is "seven billion, nine hundred eighty-seven million, five hundred twenty-three thousand, eight hundred twenty-one".