65507221 has 4 divisors (see below), whose sum is σ = 70546252. Its totient is φ = 60468192.

The previous prime is 65507161. The next prime is 65507257. The reversal of 65507221 is 12270556.

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 43744996 + 21762225 = 6614^2 + 4665^2 .

It is a cyclic number.

It is not a de Polignac number, because 65507221 - 2¹³ = 65499029 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65507221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65507261) 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 3 ways as a sum of consecutive naturals, for example, 2519496 + ... + 2519521.

It is an arithmetic number, because the mean of its divisors is an integer number (17636563).

Almost surely, 2^65507221 is an apocalyptic number.

It is an amenable number.

65507221 is a deficient number, since it is larger than the sum of its proper divisors (5039031).

65507221 is a wasteful number, since it uses less digits than its factorization.

65507221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5039030.

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 65507221 is about 8093.6531306944. The cubic root of 65507221 is about 403.1157115902.

Adding to 65507221 its reverse (12270556), we get a palindrome (77777777).

The spelling of 65507221 in words is "sixty-five million, five hundred seven thousand, two hundred twenty-one".