7538105204721 has 243 divisors, whose sum is σ = 13995004299939. Its totient is φ = 3896675887104.

The previous prime is 7538105204701. The next prime is 7538105204759. The reversal of 7538105204721 is 1274025018357.

The square root of 7538105204721 is 2745561.

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

7538105204721 is a `hidden beast` number, since 7 + 5 + 3 + 81 + 0 + 520 + 47 + 2 + 1 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 5209856465121 + 2328248739600 = 2282511^2 + 1525860^2 .

It is not a de Polignac number, because 7538105204721 - 2¹¹ = 7538105202673 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7538105204701) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 66708895561 + ... + 66708895673.

Almost surely, 2^{7538105204721} is an apocalyptic number.

7538105204721 is the 2745561-st square number.

7538105204721 is the 1372781-st centered octagonal number.

It is an amenable number.

7538105204721 is a deficient number, since it is larger than the sum of its proper divisors (6456899095218).

7538105204721 is a wasteful number, since it uses less digits than its factorization.

7538105204721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450 (or 225 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The spelling of 7538105204721 in words is "seven trillion, five hundred thirty-eight billion, one hundred five million, two hundred four thousand, seven hundred twenty-one".