8551721 has 2 divisors, whose sum is σ = 8551722. Its totient is φ = 8551720.

The previous prime is 8551687. The next prime is 8551733. The reversal of 8551721 is 1271558.

8551721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7639696 + 912025 = 2764^2 + 955^2 .

It is a cyclic number.

It is not a de Polignac number, because 8551721 - 2¹⁰ = 8550697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (8551421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4275860 + 4275861.

It is an arithmetic number, because the mean of its divisors is an integer number (4275861).

Almost surely, 2^8551721 is an apocalyptic number.

It is an amenable number.

8551721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8551721 is an equidigital number, since it uses as much as digits as its factorization.

8551721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2800, while the sum is 29.

The square root of 8551721 is about 2924.3325734259. The cubic root of 8551721 is about 204.4958541971.

The spelling of 8551721 in words is "eight million, five hundred fifty-one thousand, seven hundred twenty-one".