65166221 has 4 divisors (see below), whose sum is σ = 65497212. Its totient is φ = 64835232.

The previous prime is 65166209. The next prime is 65166223. The reversal of 65166221 is 12266156.

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 48804196 + 16362025 = 6986^2 + 4045^2 .

It is a cyclic number.

It is not a de Polignac number, because 65166221 - 2¹⁰ = 65165197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65166223) 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, 165200 + ... + 165593.

It is an arithmetic number, because the mean of its divisors is an integer number (16374303).

Almost surely, 2^65166221 is an apocalyptic number.

It is an amenable number.

65166221 is a deficient number, since it is larger than the sum of its proper divisors (330991).

65166221 is a wasteful number, since it uses less digits than its factorization.

65166221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330990.

The product of its digits is 4320, while the sum is 29.

The square root of 65166221 is about 8072.5597551210. The cubic root of 65166221 is about 402.4150169719.

The spelling of 65166221 in words is "sixty-five million, one hundred sixty-six thousand, two hundred twenty-one".