221206213 has 2 divisors, whose sum is σ = 221206214. Its totient is φ = 221206212.

The previous prime is 221206169. The next prime is 221206267. The reversal of 221206213 is 312602122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 164685889 + 56520324 = 12833^2 + 7518^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221206213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221206283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110603106 + 110603107.

It is an arithmetic number, because the mean of its divisors is an integer number (110603107).

Almost surely, 2^221206213 is an apocalyptic number.

It is an amenable number.

221206213 is a deficient number, since it is larger than the sum of its proper divisors (1).

221206213 is an equidigital number, since it uses as much as digits as its factorization.

221206213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 221206213 is about 14873.0028239088. The cubic root of 221206213 is about 604.7823482272.

Adding to 221206213 its reverse (312602122), we get a palindrome (533808335).

The spelling of 221206213 in words is "two hundred twenty-one million, two hundred six thousand, two hundred thirteen".