65550551561 has 4 divisors (see below), whose sum is σ = 71509692624. Its totient is φ = 59591410500.

The previous prime is 65550551537. The next prime is 65550551579. The reversal of 65550551561 is 16515505556.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 65550551561 - 2²⁶ = 65483442697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65550551501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2979570515 + ... + 2979570536.

It is an arithmetic number, because the mean of its divisors is an integer number (17877423156).

Almost surely, 2^65550551561 is an apocalyptic number.

It is an amenable number.

65550551561 is a deficient number, since it is larger than the sum of its proper divisors (5959141063).

65550551561 is a wasteful number, since it uses less digits than its factorization.

65550551561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5959141062.

The product of its (nonzero) digits is 562500, while the sum is 44.

The spelling of 65550551561 in words is "sixty-five billion, five hundred fifty million, five hundred fifty-one thousand, five hundred sixty-one".