65544445921 has 4 divisors (see below), whose sum is σ = 65704701700. Its totient is φ = 65384190144.

The previous prime is 65544445919. The next prime is 65544445933. The reversal of 65544445921 is 12954444556.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40860579600 + 24683866321 = 202140^2 + 157111^2 .

It is a cyclic number.

It is not a de Polignac number, because 65544445921 - 2¹ = 65544445919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65544442921) 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 3 ways as a sum of consecutive naturals, for example, 80127276 + ... + 80128093.

It is an arithmetic number, because the mean of its divisors is an integer number (16426175425).

Almost surely, 2^65544445921 is an apocalyptic number.

It is an amenable number.

65544445921 is a deficient number, since it is larger than the sum of its proper divisors (160255779).

65544445921 is a wasteful number, since it uses less digits than its factorization.

65544445921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160255778.

The product of its digits is 3456000, while the sum is 49.

The spelling of 65544445921 in words is "sixty-five billion, five hundred forty-four million, four hundred forty-five thousand, nine hundred twenty-one".