65781869 has 2 divisors, whose sum is σ = 65781870. Its totient is φ = 65781868.

The previous prime is 65781847. The next prime is 65781871. The reversal of 65781869 is 96818756.

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., 57002500 + 8779369 = 7550^2 + 2963^2 .

It is a cyclic number.

It is not a de Polignac number, because 65781869 - 2⁸ = 65781613 is a prime.

It is a super-2 number, since 2×65781869² = 8654508578266322, which contains 22 as substring.

Together with 65781871, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65781169) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32890934 + 32890935.

It is an arithmetic number, because the mean of its divisors is an integer number (32890935).

Almost surely, 2^65781869 is an apocalyptic number.

It is an amenable number.

65781869 is a deficient number, since it is larger than the sum of its proper divisors (1).

65781869 is an equidigital number, since it uses as much as digits as its factorization.

65781869 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 65781869 is about 8110.6022587722. The cubic root of 65781869 is about 403.6782986989.

It can be divided in two parts, 6 and 5781869, that added together give a palindrome (5781875).

The spelling of 65781869 in words is "sixty-five million, seven hundred eighty-one thousand, eight hundred sixty-nine".