7987921969 has 2 divisors, whose sum is σ = 7987921970. Its totient is φ = 7987921968.

The previous prime is 7987921867. The next prime is 7987921973. The reversal of 7987921969 is 9691297897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4953344400 + 3034577569 = 70380^2 + 55087^2 .

It is an emirp because it is prime and its reverse (9691297897) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7987921969 - 2¹⁵ = 7987889201 is a prime.

It is a super-2 number, since 2×7987921969² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (7987921769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3993960984 + 3993960985.

It is an arithmetic number, because the mean of its divisors is an integer number (3993960985).

Almost surely, 2^7987921969 is an apocalyptic number.

It is an amenable number.

7987921969 is a deficient number, since it is larger than the sum of its proper divisors (1).

7987921969 is an equidigital number, since it uses as much as digits as its factorization.

7987921969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30862944, while the sum is 67.

The square root of 7987921969 is about 89375.1753508769. The cubic root of 7987921969 is about 1998.9929904677.

The spelling of 7987921969 in words is "seven billion, nine hundred eighty-seven million, nine hundred twenty-one thousand, nine hundred sixty-nine".