6561578531 has 2 divisors, whose sum is σ = 6561578532. Its totient is φ = 6561578530.

The previous prime is 6561578509. The next prime is 6561578549. The reversal of 6561578531 is 1358751656.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6561578531 is a prime.

It is a super-2 number, since 2×6561578531² = 86108625636960235922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6561578561) 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 as a sum of consecutive naturals, namely, 3280789265 + 3280789266.

It is an arithmetic number, because the mean of its divisors is an integer number (3280789266).

Almost surely, 2^6561578531 is an apocalyptic number.

6561578531 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561578531 is an equidigital number, since it uses as much as digits as its factorization.

6561578531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756000, while the sum is 47.

The square root of 6561578531 is about 81003.5711002916. The cubic root of 6561578531 is about 1872.1304639568.

The spelling of 6561578531 in words is "six billion, five hundred sixty-one million, five hundred seventy-eight thousand, five hundred thirty-one".