7201216721 has 2 divisors, whose sum is σ = 7201216722. Its totient is φ = 7201216720.

The previous prime is 7201216709. The next prime is 7201216747. The reversal of 7201216721 is 1276121027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7180867600 + 20349121 = 84740^2 + 4511^2 .

It is a cyclic number.

It is not a de Polignac number, because 7201216721 - 2¹⁸ = 7200954577 is a prime.

It is not a weakly prime, because it can be changed into another prime (7201212721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3600608360 + 3600608361.

It is an arithmetic number, because the mean of its divisors is an integer number (3600608361).

Almost surely, 2^7201216721 is an apocalyptic number.

It is an amenable number.

7201216721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7201216721 is an equidigital number, since it uses as much as digits as its factorization.

7201216721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 7201216721 is about 84859.9830367647. The cubic root of 7201216721 is about 1931.0875344931.

Adding to 7201216721 its reverse (1276121027), we get a palindrome (8477337748).

The spelling of 7201216721 in words is "seven billion, two hundred one million, two hundred sixteen thousand, seven hundred twenty-one".