4521721 has 2 divisors, whose sum is σ = 4521722. Its totient is φ = 4521720.

The previous prime is 4521707. The next prime is 4521739. The reversal of 4521721 is 1271254.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3980025 + 541696 = 1995^2 + 736^2 .

It is a cyclic number.

It is not a de Polignac number, because 4521721 - 2⁵ = 4521689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 4521692 and 4521701.

It is not a weakly prime, because it can be changed into another prime (4521761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2260860 + 2260861.

It is an arithmetic number, because the mean of its divisors is an integer number (2260861).

Almost surely, 2^4521721 is an apocalyptic number.

It is an amenable number.

4521721 is a deficient number, since it is larger than the sum of its proper divisors (1).

4521721 is an equidigital number, since it uses as much as digits as its factorization.

4521721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 560, while the sum is 22.

The square root of 4521721 is about 2126.4338691810. The cubic root of 4521721 is about 165.3615701245.

Adding to 4521721 its reverse (1271254), we get a palindrome (5792975).

The spelling of 4521721 in words is "four million, five hundred twenty-one thousand, seven hundred twenty-one".