7843982105521 has 9 divisors (see below), whose sum is σ = 7901211752811. Its totient is φ = 7787164081464.

The previous prime is 7843982105447. The next prime is 7843982105527. The reversal of 7843982105521 is 1255012893487.

The square root of 7843982105521 is 2800711.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3600464505121 + 4243517600400 = 1897489^2 + 2059980^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7843982105521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7843982105527) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 389288755 + ... + 389308903.

It is an arithmetic number, because the mean of its divisors is an integer number (877912416979).

Almost surely, 2^{7843982105521} is an apocalyptic number.

7843982105521 is the 2800711-st square number.

7843982105521 is the 1400356-th centered octagonal number.

It is an amenable number.

7843982105521 is a deficient number, since it is larger than the sum of its proper divisors (57229647290).

7843982105521 is an frugal number, since it uses more digits than its factorization.

7843982105521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40576 (or 20288 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 55.

The spelling of 7843982105521 in words is "seven trillion, eight hundred forty-three billion, nine hundred eighty-two million, one hundred five thousand, five hundred twenty-one".