7843643777261 has 2 divisors, whose sum is σ = 7843643777262. Its totient is φ = 7843643777260.

The previous prime is 7843643777231. The next prime is 7843643777309. The reversal of 7843643777261 is 1627773463487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5340859660900 + 2502784116361 = 2311030^2 + 1582019^2 .

It is a cyclic number.

It is not a de Polignac number, because 7843643777261 - 2¹⁸ = 7843643515117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7843643777231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3921821888630 + 3921821888631.

It is an arithmetic number, because the mean of its divisors is an integer number (3921821888631).

Almost surely, 2^{7843643777261} is an apocalyptic number.

It is an amenable number.

7843643777261 is a deficient number, since it is larger than the sum of its proper divisors (1).

7843643777261 is an equidigital number, since it uses as much as digits as its factorization.

7843643777261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 199148544, while the sum is 65.

The spelling of 7843643777261 in words is "seven trillion, eight hundred forty-three billion, six hundred forty-three million, seven hundred seventy-seven thousand, two hundred sixty-one".