7987921867 has 2 divisors, whose sum is σ = 7987921868. Its totient is φ = 7987921866.

The previous prime is 7987921847. The next prime is 7987921969. The reversal of 7987921867 is 7681297897.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7987921867 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7987921799 and 7987921808.

It is not a weakly prime, because it can be changed into another prime (7987921847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3993960933 + 3993960934.

It is an arithmetic number, because the mean of its divisors is an integer number (3993960934).

Almost surely, 2^7987921867 is an apocalyptic number.

7987921867 is a deficient number, since it is larger than the sum of its proper divisors (1).

7987921867 is an equidigital number, since it uses as much as digits as its factorization.

7987921867 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21337344, while the sum is 64.

The square root of 7987921867 is about 89375.1747802487. The cubic root of 7987921867 is about 1998.9929819591.

The spelling of 7987921867 in words is "seven billion, nine hundred eighty-seven million, nine hundred twenty-one thousand, eight hundred sixty-seven".