221554213 has 2 divisors, whose sum is σ = 221554214. Its totient is φ = 221554212.

The previous prime is 221554199. The next prime is 221554219. The reversal of 221554213 is 312455122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 219543489 + 2010724 = 14817^2 + 1418^2 .

It is a cyclic number.

It is not a de Polignac number, because 221554213 - 2⁵ = 221554181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221554219) 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, 110777106 + 110777107.

It is an arithmetic number, because the mean of its divisors is an integer number (110777107).

Almost surely, 2^221554213 is an apocalyptic number.

It is an amenable number.

221554213 is a deficient number, since it is larger than the sum of its proper divisors (1).

221554213 is an equidigital number, since it uses as much as digits as its factorization.

221554213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 25.

The square root of 221554213 is about 14884.6972760617. The cubic root of 221554213 is about 605.0993284539.

Subtracting 221554213 from its reverse (312455122), we obtain a palindrome (90900909).

The spelling of 221554213 in words is "two hundred twenty-one million, five hundred fifty-four thousand, two hundred thirteen".