561689983 has 2 divisors, whose sum is σ = 561689984. Its totient is φ = 561689982.

The previous prime is 561689981. The next prime is 561690029. The reversal of 561689983 is 389986165.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 561689983 - 2¹ = 561689981 is a prime.

Together with 561689981, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561689981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280844991 + 280844992.

It is an arithmetic number, because the mean of its divisors is an integer number (280844992).

Almost surely, 2^561689983 is an apocalyptic number.

561689983 is a deficient number, since it is larger than the sum of its proper divisors (1).

561689983 is an equidigital number, since it uses as much as digits as its factorization.

561689983 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2799360, while the sum is 55.

The square root of 561689983 is about 23699.9996413502. Note that the first 3 decimals coincide. The cubic root of 561689983 is about 825.0853822865.

The spelling of 561689983 in words is "five hundred sixty-one million, six hundred eighty-nine thousand, nine hundred eighty-three".