65561987 has 2 divisors, whose sum is σ = 65561988. Its totient is φ = 65561986.

The previous prime is 65561959. The next prime is 65562019. The reversal of 65561987 is 78916556.

65561987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 65561987 - 2⁸ = 65561731 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (65561917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32780993 + 32780994.

It is an arithmetic number, because the mean of its divisors is an integer number (32780994).

Almost surely, 2^65561987 is an apocalyptic number.

65561987 is a deficient number, since it is larger than the sum of its proper divisors (1).

65561987 is an equidigital number, since it uses as much as digits as its factorization.

65561987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 453600, while the sum is 47.

The square root of 65561987 is about 8097.0356921530. The cubic root of 65561987 is about 403.2280192372.

The spelling of 65561987 in words is "sixty-five million, five hundred sixty-one thousand, nine hundred eighty-seven".