221858213 has 2 divisors, whose sum is σ = 221858214. Its totient is φ = 221858212.

The previous prime is 221858209. The next prime is 221858249. The reversal of 221858213 is 312858122.

It is a happy number.

221858213 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 192460129 + 29398084 = 13873^2 + 5422^2 .

It is a cyclic number.

It is not a de Polignac number, because 221858213 - 2² = 221858209 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221858213.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221858513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110929106 + 110929107.

It is an arithmetic number, because the mean of its divisors is an integer number (110929107).

Almost surely, 2^221858213 is an apocalyptic number.

It is an amenable number.

221858213 is a deficient number, since it is larger than the sum of its proper divisors (1).

221858213 is an equidigital number, since it uses as much as digits as its factorization.

221858213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7680, while the sum is 32.

The square root of 221858213 is about 14894.9056056089. The cubic root of 221858213 is about 605.3759592060.

Subtracting 221858213 from its reverse (312858122), we obtain a palindrome (90999909).

The spelling of 221858213 in words is "two hundred twenty-one million, eight hundred fifty-eight thousand, two hundred thirteen".