6612721 has 2 divisors, whose sum is σ = 6612722. Its totient is φ = 6612720.

The previous prime is 6612701. The next prime is 6612731. The reversal of 6612721 is 1272166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5085025 + 1527696 = 2255^2 + 1236^2 .

It is a cyclic number.

It is not a de Polignac number, because 6612721 - 2¹¹ = 6610673 is a prime.

It is not a weakly prime, because it can be changed into another prime (6612701) 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, 3306360 + 3306361.

It is an arithmetic number, because the mean of its divisors is an integer number (3306361).

Almost surely, 2^6612721 is an apocalyptic number.

It is an amenable number.

6612721 is a deficient number, since it is larger than the sum of its proper divisors (1).

6612721 is an equidigital number, since it uses as much as digits as its factorization.

6612721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 25.

The square root of 6612721 is about 2571.5211451590. The cubic root of 6612721 is about 187.6981821570.

Adding to 6612721 its reverse (1272166), we get a palindrome (7884887).

The spelling of 6612721 in words is "six million, six hundred twelve thousand, seven hundred twenty-one".