6561539 has 2 divisors, whose sum is σ = 6561540. Its totient is φ = 6561538.

The previous prime is 6561521. The next prime is 6561547. The reversal of 6561539 is 9351656.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6561539 - 2⁸ = 6561283 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 6561499 and 6561508.

It is not a weakly prime, because it can be changed into another prime (6561589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280769 + 3280770.

It is an arithmetic number, because the mean of its divisors is an integer number (3280770).

Almost surely, 2^6561539 is an apocalyptic number.

6561539 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561539 is an equidigital number, since it uses as much as digits as its factorization.

6561539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24300, while the sum is 35.

The square root of 6561539 is about 2561.5501166286. The cubic root of 6561539 is about 187.2126704326.

The spelling of 6561539 in words is "six million, five hundred sixty-one thousand, five hundred thirty-nine".