65091777561 has 6 divisors (see below), whose sum is σ = 94021456490. Its totient is φ = 43394518368.

The previous prime is 65091777559. The next prime is 65091777587. The reversal of 65091777561 is 16577719056.

65091777561 is a `hidden beast` number, since 6 + 5 + 0 + 9 + 1 + 7 + 77 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 47794267161 + 17297510400 = 218619^2 + 131520^2 .

It is not a de Polignac number, because 65091777561 - 2¹ = 65091777559 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 65091777498 and 65091777507.

It is not an unprimeable number, because it can be changed into a prime (65091779561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3616209856 + ... + 3616209873.

Almost surely, 2^65091777561 is an apocalyptic number.

It is an amenable number.

65091777561 is a deficient number, since it is larger than the sum of its proper divisors (28929678929).

65091777561 is a wasteful number, since it uses less digits than its factorization.

65091777561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7232419735 (or 7232419732 counting only the distinct ones).

The product of its (nonzero) digits is 2778300, while the sum is 54.

The spelling of 65091777561 in words is "sixty-five billion, ninety-one million, seven hundred seventy-seven thousand, five hundred sixty-one".