8567538721 has 15 divisors (see below), whose sum is σ = 10000161011. Its totient is φ = 7339717056.

The previous prime is 8567538641. The next prime is 8567538731. The reversal of 8567538721 is 1278357658.

It is a happy number.

The square root of 8567538721 is 92561.

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., 4126649121 + 4440889600 = 64239^2 + 66640^2 .

It is not a de Polignac number, because 8567538721 - 2¹⁵ = 8567505953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8567538731) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 4534545 + ... + 4536433.

Almost surely, 2^8567538721 is an apocalyptic number.

8567538721 is the 92561-st square number.

8567538721 is the 46281-st centered octagonal number.

It is an amenable number.

8567538721 is a deficient number, since it is larger than the sum of its proper divisors (1432622290).

8567538721 is an frugal number, since it uses more digits than its factorization.

8567538721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3806 (or 1896 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 52.

The cubic root of 8567538721 is about 2046.2185870080.

The spelling of 8567538721 in words is "eight billion, five hundred sixty-seven million, five hundred thirty-eight thousand, seven hundred twenty-one".