221540017 has 2 divisors, whose sum is σ = 221540018. Its totient is φ = 221540016.

The previous prime is 221540009. The next prime is 221540021. The reversal of 221540017 is 710045122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 221533456 + 6561 = 14884^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 221540017 - 2³ = 221540009 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221540017.

It is not a weakly prime, because it can be changed into another prime (221540027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110770008 + 110770009.

It is an arithmetic number, because the mean of its divisors is an integer number (110770009).

Almost surely, 2^221540017 is an apocalyptic number.

It is an amenable number.

221540017 is a deficient number, since it is larger than the sum of its proper divisors (1).

221540017 is an equidigital number, since it uses as much as digits as its factorization.

221540017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 221540017 is about 14884.2204028293. The cubic root of 221540017 is about 605.0864043431.

Adding to 221540017 its reverse (710045122), we get a palindrome (931585139).

The spelling of 221540017 in words is "two hundred twenty-one million, five hundred forty thousand, seventeen".