20016221 has 2 divisors, whose sum is σ = 20016222. Its totient is φ = 20016220.

The previous prime is 20016193. The next prime is 20016229. The reversal of 20016221 is 12261002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15960025 + 4056196 = 3995^2 + 2014^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20016221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20016196 and 20016205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20016229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10008110 + 10008111.

It is an arithmetic number, because the mean of its divisors is an integer number (10008111).

Almost surely, 2^20016221 is an apocalyptic number.

It is an amenable number.

20016221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20016221 is an equidigital number, since it uses as much as digits as its factorization.

20016221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 20016221 is about 4473.9491503592. The cubic root of 20016221 is about 271.5151261092.

Adding to 20016221 its reverse (12261002), we get a palindrome (32277223).

The spelling of 20016221 in words is "twenty million, sixteen thousand, two hundred twenty-one".