20550217 has 2 divisors, whose sum is σ = 20550218. Its totient is φ = 20550216.

The previous prime is 20550209. The next prime is 20550223. The reversal of 20550217 is 71205502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18181696 + 2368521 = 4264^2 + 1539^2 .

It is a cyclic number.

It is not a de Polignac number, because 20550217 - 2³ = 20550209 is a prime.

It is a super-2 number, since 2×20550217² = 844622837494178, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20550287) 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, 10275108 + 10275109.

It is an arithmetic number, because the mean of its divisors is an integer number (10275109).

Almost surely, 2^20550217 is an apocalyptic number.

It is an amenable number.

20550217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20550217 is an equidigital number, since it uses as much as digits as its factorization.

20550217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 20550217 is about 4533.2347170646. The cubic root of 20550217 is about 273.9084754786.

Adding to 20550217 its reverse (71205502), we get a palindrome (91755719).

The spelling of 20550217 in words is "twenty million, five hundred fifty thousand, two hundred seventeen".