561305887 has 2 divisors, whose sum is σ = 561305888. Its totient is φ = 561305886.

The previous prime is 561305861. The next prime is 561305893. The reversal of 561305887 is 788503165.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 561305887 - 2²³ = 552917279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561305827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280652943 + 280652944.

It is an arithmetic number, because the mean of its divisors is an integer number (280652944).

Almost surely, 2^561305887 is an apocalyptic number.

561305887 is a deficient number, since it is larger than the sum of its proper divisors (1).

561305887 is an equidigital number, since it uses as much as digits as its factorization.

561305887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 201600, while the sum is 43.

The square root of 561305887 is about 23691.8949643122. The cubic root of 561305887 is about 824.8972688733.

The spelling of 561305887 in words is "five hundred sixty-one million, three hundred five thousand, eight hundred eighty-seven".