6604105721 has 2 divisors, whose sum is σ = 6604105722. Its totient is φ = 6604105720.

The previous prime is 6604105661. The next prime is 6604105727. The reversal of 6604105721 is 1275014066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6599287696 + 4818025 = 81236^2 + 2195^2 .

It is a cyclic number.

It is not a de Polignac number, because 6604105721 - 2⁶ = 6604105657 is a prime.

It is a super-2 number, since 2×6604105721² = 87228424748289859682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6604105727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3302052860 + 3302052861.

It is an arithmetic number, because the mean of its divisors is an integer number (3302052861).

Almost surely, 2^6604105721 is an apocalyptic number.

It is an amenable number.

6604105721 is a deficient number, since it is larger than the sum of its proper divisors (1).

6604105721 is an equidigital number, since it uses as much as digits as its factorization.

6604105721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 6604105721 is about 81265.6490837303. The cubic root of 6604105721 is about 1876.1663352900.

Adding to 6604105721 its reverse (1275014066), we get a palindrome (7879119787).

The spelling of 6604105721 in words is "six billion, six hundred four million, one hundred five thousand, seven hundred twenty-one".