561661567 has 2 divisors, whose sum is σ = 561661568. Its totient is φ = 561661566.

The previous prime is 561661559. The next prime is 561661577. The reversal of 561661567 is 765166165.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 561661567 - 2³ = 561661559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561661547) 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, 280830783 + 280830784.

It is an arithmetic number, because the mean of its divisors is an integer number (280830784).

Almost surely, 2^561661567 is an apocalyptic number.

561661567 is a deficient number, since it is larger than the sum of its proper divisors (1).

561661567 is an equidigital number, since it uses as much as digits as its factorization.

561661567 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 43.

The square root of 561661567 is about 23699.4001400879. The cubic root of 561661567 is about 825.0714683112.

The spelling of 561661567 in words is "five hundred sixty-one million, six hundred sixty-one thousand, five hundred sixty-seven".