224021521 has 2 divisors, whose sum is σ = 224021522. Its totient is φ = 224021520.

The previous prime is 224021519. The next prime is 224021527. The reversal of 224021521 is 125120422.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 210250000 + 13771521 = 14500^2 + 3711^2 .

It is a cyclic number.

It is not a de Polignac number, because 224021521 - 2¹ = 224021519 is a prime.

Together with 224021519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (224021527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112010760 + 112010761.

It is an arithmetic number, because the mean of its divisors is an integer number (112010761).

Almost surely, 2^224021521 is an apocalyptic number.

It is an amenable number.

224021521 is a deficient number, since it is larger than the sum of its proper divisors (1).

224021521 is an equidigital number, since it uses as much as digits as its factorization.

224021521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 224021521 is about 14967.3484959762. The cubic root of 224021521 is about 607.3372432854.

Adding to 224021521 its reverse (125120422), we get a palindrome (349141943).

The spelling of 224021521 in words is "two hundred twenty-four million, twenty-one thousand, five hundred twenty-one".