65555221 has 8 divisors (see below), whose sum is σ = 68529024. Its totient is φ = 62591760.

The previous prime is 65555209. The next prime is 65555257. The reversal of 65555221 is 12255556.

65555221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 65555221 - 2⁷ = 65555093 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65555261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12255 + ... + 16771.

It is an arithmetic number, because the mean of its divisors is an integer number (8566128).

Almost surely, 2^65555221 is an apocalyptic number.

It is an amenable number.

65555221 is a deficient number, since it is larger than the sum of its proper divisors (2973803).

65555221 is a wasteful number, since it uses less digits than its factorization.

65555221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5171.

The product of its digits is 15000, while the sum is 31.

The square root of 65555221 is about 8096.6178741497. The cubic root of 65555221 is about 403.2141477101.

The spelling of 65555221 in words is "sixty-five million, five hundred fifty-five thousand, two hundred twenty-one".