221204161 has 2 divisors, whose sum is σ = 221204162. Its totient is φ = 221204160.

The previous prime is 221204129. The next prime is 221204197. The reversal of 221204161 is 161402122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118810000 + 102394161 = 10900^2 + 10119^2 .

It is a cyclic number.

It is not a de Polignac number, because 221204161 - 2⁵ = 221204129 is a prime.

It is not a weakly prime, because it can be changed into another prime (221204261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110602080 + 110602081.

It is an arithmetic number, because the mean of its divisors is an integer number (110602081).

Almost surely, 2^221204161 is an apocalyptic number.

It is an amenable number.

221204161 is a deficient number, since it is larger than the sum of its proper divisors (1).

221204161 is an equidigital number, since it uses as much as digits as its factorization.

221204161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 221204161 is about 14872.9338396969. The cubic root of 221204161 is about 604.7804781513.

Adding to 221204161 its reverse (161402122), we get a palindrome (382606283).

The spelling of 221204161 in words is "two hundred twenty-one million, two hundred four thousand, one hundred sixty-one".