65640237281 has 2 divisors, whose sum is σ = 65640237282. Its totient is φ = 65640237280.

The previous prime is 65640237263. The next prime is 65640237337. The reversal of 65640237281 is 18273204656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60130886656 + 5509350625 = 245216^2 + 74225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65640237281 is a prime.

It is a super-2 number, since 2×65640237281² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (65640237181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32820118640 + 32820118641.

It is an arithmetic number, because the mean of its divisors is an integer number (32820118641).

Almost surely, 2^65640237281 is an apocalyptic number.

It is an amenable number.

65640237281 is a deficient number, since it is larger than the sum of its proper divisors (1).

65640237281 is an equidigital number, since it uses as much as digits as its factorization.

65640237281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 483840, while the sum is 44.

The spelling of 65640237281 in words is "sixty-five billion, six hundred forty million, two hundred thirty-seven thousand, two hundred eighty-one".