65941256561 has 2 divisors, whose sum is σ = 65941256562. Its totient is φ = 65941256560.

The previous prime is 65941256539. The next prime is 65941256651. The reversal of 65941256561 is 16565214956.

Together with next prime (65941256651) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35851150336 + 30090106225 = 189344^2 + 173465^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65941256561 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (65941256501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32970628280 + 32970628281.

It is an arithmetic number, because the mean of its divisors is an integer number (32970628281).

Almost surely, 2^65941256561 is an apocalyptic number.

It is an amenable number.

65941256561 is a deficient number, since it is larger than the sum of its proper divisors (1).

65941256561 is an equidigital number, since it uses as much as digits as its factorization.

65941256561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944000, while the sum is 50.

The spelling of 65941256561 in words is "sixty-five billion, nine hundred forty-one million, two hundred fifty-six thousand, five hundred sixty-one".