561999943 has 2 divisors, whose sum is σ = 561999944. Its totient is φ = 561999942.

The previous prime is 561999941. The next prime is 561999959. The reversal of 561999943 is 349999165.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 561999943 - 2¹ = 561999941 is a prime.

Together with 561999941, 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 (561999941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280999971 + 280999972.

It is an arithmetic number, because the mean of its divisors is an integer number (280999972).

Almost surely, 2^561999943 is an apocalyptic number.

561999943 is a deficient number, since it is larger than the sum of its proper divisors (1).

561999943 is an equidigital number, since it uses as much as digits as its factorization.

561999943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2361960, while the sum is 55.

The square root of 561999943 is about 23706.5379800594. The cubic root of 561999943 is about 825.2371246145.

The spelling of 561999943 in words is "five hundred sixty-one million, nine hundred ninety-nine thousand, nine hundred forty-three".