8006561 has 2 divisors, whose sum is σ = 8006562. Its totient is φ = 8006560.

The previous prime is 8006549. The next prime is 8006563. The reversal of 8006561 is 1656008.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5494336 + 2512225 = 2344^2 + 1585^2 .

It is a cyclic number.

It is not a de Polignac number, because 8006561 - 2²² = 3812257 is a prime.

Together with 8006563, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8006561.

It is not a weakly prime, because it can be changed into another prime (8006563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4003280 + 4003281.

It is an arithmetic number, because the mean of its divisors is an integer number (4003281).

Almost surely, 2^8006561 is an apocalyptic number.

It is an amenable number.

8006561 is a deficient number, since it is larger than the sum of its proper divisors (1).

8006561 is an equidigital number, since it uses as much as digits as its factorization.

8006561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 8006561 is about 2829.5867189397. The cubic root of 8006561 is about 200.0546600600.

The spelling of 8006561 in words is "eight million, six thousand, five hundred sixty-one".