7845775981 has 2 divisors, whose sum is σ = 7845775982. Its totient is φ = 7845775980.

The previous prime is 7845775979. The next prime is 7845775999. The reversal of 7845775981 is 1895775487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6620425956 + 1225350025 = 81366^2 + 35005^2 .

It is an emirp because it is prime and its reverse (1895775487) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7845775981 - 2¹ = 7845775979 is a prime.

It is a super-2 number, since 2×7845775981² (a number of 21 digits) contains 22 as substring.

Together with 7845775979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7845775481) 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, 3922887990 + 3922887991.

It is an arithmetic number, because the mean of its divisors is an integer number (3922887991).

Almost surely, 2^7845775981 is an apocalyptic number.

It is an amenable number.

7845775981 is a deficient number, since it is larger than the sum of its proper divisors (1).

7845775981 is an equidigital number, since it uses as much as digits as its factorization.

7845775981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19756800, while the sum is 61.

The square root of 7845775981 is about 88576.3850075177. The cubic root of 7845775981 is about 1987.0645154069.

The spelling of 7845775981 in words is "seven billion, eight hundred forty-five million, seven hundred seventy-five thousand, nine hundred eighty-one".