65564221 has 2 divisors, whose sum is σ = 65564222. Its totient is φ = 65564220.

The previous prime is 65564209. The next prime is 65564243. The reversal of 65564221 is 12246556.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34047225 + 31516996 = 5835^2 + 5614^2 .

It is a cyclic number.

It is not a de Polignac number, because 65564221 - 2¹¹ = 65562173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65564921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32782110 + 32782111.

It is an arithmetic number, because the mean of its divisors is an integer number (32782111).

Almost surely, 2^65564221 is an apocalyptic number.

It is an amenable number.

65564221 is a deficient number, since it is larger than the sum of its proper divisors (1).

65564221 is an equidigital number, since it uses as much as digits as its factorization.

65564221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 31.

The square root of 65564221 is about 8097.1736426978. The cubic root of 65564221 is about 403.2325991328.

The spelling of 65564221 in words is "sixty-five million, five hundred sixty-four thousand, two hundred twenty-one".