220006561 has 2 divisors, whose sum is σ = 220006562. Its totient is φ = 220006560.

The previous prime is 220006541. The next prime is 220006603. The reversal of 220006561 is 165600022.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 141134400 + 78872161 = 11880^2 + 8881^2 .

It is a cyclic number.

It is not a de Polignac number, because 220006561 - 2⁷ = 220006433 is a prime.

It is a super-3 number, since 3×220006561³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (220006511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110003280 + 110003281.

It is an arithmetic number, because the mean of its divisors is an integer number (110003281).

Almost surely, 2^220006561 is an apocalyptic number.

It is an amenable number.

220006561 is a deficient number, since it is larger than the sum of its proper divisors (1).

220006561 is an equidigital number, since it uses as much as digits as its factorization.

220006561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 220006561 is about 14832.6181438072. The cubic root of 220006561 is about 603.6870747588.

Adding to 220006561 its reverse (165600022), we get a palindrome (385606583).

It can be divided in two parts, 22000 and 6561, that added together give a 4-th power (28561 = 13⁴).

The spelling of 220006561 in words is "two hundred twenty million, six thousand, five hundred sixty-one".