8220867561 has 9 divisors (see below), whose sum is σ = 11874979389. Its totient is φ = 5480397036.

The previous prime is 8220867559. The next prime is 8220867583. The reversal of 8220867561 is 1657680228.

The square root of 8220867561 is 90669.

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

8220867561 is a `hidden beast` number, since 8 + 2 + 2 + 0 + 86 + 7 + 561 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 8220867561 - 2¹ = 8220867559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8220863561) 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 in 8 ways as a sum of consecutive naturals, for example, 256896 + ... + 287118.

Almost surely, 2^8220867561 is an apocalyptic number.

8220867561 is the 90669-th square number.

8220867561 is the 45335-th centered octagonal number.

It is an amenable number.

8220867561 is a deficient number, since it is larger than the sum of its proper divisors (3654111828).

8220867561 is an frugal number, since it uses more digits than its factorization.

8220867561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60452 (or 30226 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The cubic root of 8220867561 is about 2018.2387976138.

It can be divided in two parts, 82208 and 67561, that added together give a square (149769 = 387²).

The spelling of 8220867561 in words is "eight billion, two hundred twenty million, eight hundred sixty-seven thousand, five hundred sixty-one".