65221 has 8 divisors (see below), whose sum is σ = 73080. Its totient is φ = 57792.

The previous prime is 65213. The next prime is 65239. The reversal of 65221 is 12256.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 12321 + 52900 = 111^2 + 230^2 .

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 65221 - 2³ = 65213 is a prime.

It is a nialpdrome in base 10 and base 16.

It is a junction number, because it is equal to n+sod(n) for n = 65195 and 65204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291 + ... + 463.

It is an arithmetic number, because the mean of its divisors is an integer number (9135).

2⁶⁵²²¹ is an apocalyptic number.

It is an amenable number.

65221 is a deficient number, since it is larger than the sum of its proper divisors (7859).

65221 is a wasteful number, since it uses less digits than its factorization.

65221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215.

The product of its digits is 120, while the sum is 16.

The square root of 65221 is about 255.3840245591. The cubic root of 65221 is about 40.2527742645.

Adding to 65221 its product of digits (120), we get a triangular number (65341 = T₃₆₁).

Adding to 65221 its reverse (12256), we get a palindrome (77477).

It can be divided in two parts, 65 and 221, that multiplied together give a triangular number (14365 = T₁₆₉).

The spelling of 65221 in words is "sixty-five thousand, two hundred twenty-one".