221004521 has 2 divisors, whose sum is σ = 221004522. Its totient is φ = 221004520.

The previous prime is 221004503. The next prime is 221004529. The reversal of 221004521 is 125400122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115326121 + 105678400 = 10739^2 + 10280^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221004521 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221004521.

It is not a weakly prime, because it can be changed into another prime (221004529) 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, 110502260 + 110502261.

It is an arithmetic number, because the mean of its divisors is an integer number (110502261).

Almost surely, 2^221004521 is an apocalyptic number.

It is an amenable number.

221004521 is a deficient number, since it is larger than the sum of its proper divisors (1).

221004521 is an equidigital number, since it uses as much as digits as its factorization.

221004521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 221004521 is about 14866.2208042259. The cubic root of 221004521 is about 604.5984823048.

Adding to 221004521 its reverse (125400122), we get a palindrome (346404643).

The spelling of 221004521 in words is "two hundred twenty-one million, four thousand, five hundred twenty-one".