221217565 has 16 divisors (see below), whose sum is σ = 278466048. Its totient is φ = 168385536.

The previous prime is 221217559. The next prime is 221217587. The reversal of 221217565 is 565712122.

It is a cyclic number.

It is not a de Polignac number, because 221217565 - 2⁵ = 221217533 is a prime.

It is a super-2 number, since 2×221217565² = 97874422129058450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17212 + ... + 27178.

It is an arithmetic number, because the mean of its divisors is an integer number (17404128).

Almost surely, 2^221217565 is an apocalyptic number.

It is an amenable number.

221217565 is a deficient number, since it is larger than the sum of its proper divisors (57248483).

221217565 is a wasteful number, since it uses less digits than its factorization.

221217565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10188.

The product of its digits is 8400, while the sum is 31.

The square root of 221217565 is about 14873.3844500840. The cubic root of 221217565 is about 604.7926935843.

Adding to 221217565 its reverse (565712122), we get a palindrome (786929687).

The spelling of 221217565 in words is "two hundred twenty-one million, two hundred seventeen thousand, five hundred sixty-five".