65987681 has 2 divisors, whose sum is σ = 65987682. Its totient is φ = 65987680.

The previous prime is 65987657. The next prime is 65987683. The reversal of 65987681 is 18678956.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63856081 + 2131600 = 7991^2 + 1460^2 .

It is a cyclic number.

It is not a de Polignac number, because 65987681 - 2⁶ = 65987617 is a prime.

It is a super-2 number, since 2×65987681² = 8708748087515522, which contains 22 as substring.

Together with 65987683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (65987683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32993840 + 32993841.

It is an arithmetic number, because the mean of its divisors is an integer number (32993841).

Almost surely, 2^65987681 is an apocalyptic number.

It is an amenable number.

65987681 is a deficient number, since it is larger than the sum of its proper divisors (1).

65987681 is an equidigital number, since it uses as much as digits as its factorization.

65987681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 50.

The square root of 65987681 is about 8123.2801872150. The cubic root of 65987681 is about 404.0988570453.

The spelling of 65987681 in words is "sixty-five million, nine hundred eighty-seven thousand, six hundred eighty-one".