8681721 has 8 divisors (see below), whose sum is σ = 11593344. Its totient is φ = 5778960.

The previous prime is 8681707. The next prime is 8681731. The reversal of 8681721 is 1271868.

It is a happy number.

8681721 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8681721 - 2¹⁰ = 8680697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8681731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 576 + ... + 4206.

It is an arithmetic number, because the mean of its divisors is an integer number (1449168).

Almost surely, 2^8681721 is an apocalyptic number.

It is an amenable number.

8681721 is a deficient number, since it is larger than the sum of its proper divisors (2911623).

8681721 is a wasteful number, since it uses less digits than its factorization.

8681721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4431.

The product of its digits is 5376, while the sum is 33.

The square root of 8681721 is about 2946.4760307866. The cubic root of 8681721 is about 205.5268699954.

The spelling of 8681721 in words is "eight million, six hundred eighty-one thousand, seven hundred twenty-one".