8081721 has 16 divisors (see below), whose sum is σ = 12253120. Its totient is φ = 5261760.

The previous prime is 8081719. The next prime is 8081737. The reversal of 8081721 is 1271808.

It is not a de Polignac number, because 8081721 - 2¹ = 8081719 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8081771) 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 in 15 ways as a sum of consecutive naturals, for example, 2320 + ... + 4641.

It is an arithmetic number, because the mean of its divisors is an integer number (765820).

Almost surely, 2^8081721 is an apocalyptic number.

It is an amenable number.

8081721 is a deficient number, since it is larger than the sum of its proper divisors (4171399).

8081721 is a wasteful number, since it uses less digits than its factorization.

8081721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7013 (or 7007 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 8081721 is about 2842.8367874361. The cubic root of 8081721 is about 200.6787025423.

The spelling of 8081721 in words is "eight million, eighty-one thousand, seven hundred twenty-one".