8271721 has 2 divisors, whose sum is σ = 8271722. Its totient is φ = 8271720.

The previous prime is 8271647. The next prime is 8271727. The reversal of 8271721 is 1271728.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7639696 + 632025 = 2764^2 + 795^2 .

It is a cyclic number.

It is not a de Polignac number, because 8271721 - 2¹⁵ = 8238953 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8271721.

It is not a weakly prime, because it can be changed into another prime (8271727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4135860 + 4135861.

It is an arithmetic number, because the mean of its divisors is an integer number (4135861).

Almost surely, 2^8271721 is an apocalyptic number.

It is an amenable number.

8271721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8271721 is an equidigital number, since it uses as much as digits as its factorization.

8271721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1568, while the sum is 28.

The square root of 8271721 is about 2876.0599785123. The cubic root of 8271721 is about 202.2391785059.

The spelling of 8271721 in words is "eight million, two hundred seventy-one thousand, seven hundred twenty-one".