65550561561 has 24 divisors (see below), whose sum is σ = 95974819200. Its totient is φ = 43107876000.

The previous prime is 65550561551. The next prime is 65550561641. The reversal of 65550561561 is 16516505556.

It is not a de Polignac number, because 65550561561 - 2⁹ = 65550561049 is a prime.

It is a super-2 number, since 2×65550561561² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (65550561551) 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 in 23 ways as a sum of consecutive naturals, for example, 113290 + ... + 379388.

It is an arithmetic number, because the mean of its divisors is an integer number (3998950800).

Almost surely, 2^65550561561 is an apocalyptic number.

It is an amenable number.

65550561561 is a deficient number, since it is larger than the sum of its proper divisors (30424257639).

65550561561 is a wasteful number, since it uses less digits than its factorization.

65550561561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266477 (or 266474 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 65550561561 in words is "sixty-five billion, five hundred fifty million, five hundred sixty-one thousand, five hundred sixty-one".