4221521 has 2 divisors, whose sum is σ = 4221522. Its totient is φ = 4221520.

The previous prime is 4221499. The next prime is 4221533. The reversal of 4221521 is 1251224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2560000 + 1661521 = 1600^2 + 1289^2 .

It is a cyclic number.

It is not a de Polignac number, because 4221521 - 2¹⁰ = 4220497 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 4221521.

It is not a weakly prime, because it can be changed into another prime (4221541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2110760 + 2110761.

It is an arithmetic number, because the mean of its divisors is an integer number (2110761).

Almost surely, 2^4221521 is an apocalyptic number.

It is an amenable number.

4221521 is a deficient number, since it is larger than the sum of its proper divisors (1).

4221521 is an equidigital number, since it uses as much as digits as its factorization.

4221521 is an evil number, because the sum of its binary digits is even.

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

The square root of 4221521 is about 2054.6340306731. The cubic root of 4221521 is about 161.6179714231.

Adding to 4221521 its reverse (1251224), we get a palindrome (5472745).

The spelling of 4221521 in words is "four million, two hundred twenty-one thousand, five hundred twenty-one".