8817721 has 4 divisors (see below), whose sum is σ = 9619344. Its totient is φ = 8016100.

The previous prime is 8817701. The next prime is 8817751. The reversal of 8817721 is 1277188.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8817721 - 2⁵ = 8817689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8817701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400795 + ... + 400816.

It is an arithmetic number, because the mean of its divisors is an integer number (2404836).

Almost surely, 2^8817721 is an apocalyptic number.

It is an amenable number.

8817721 is a deficient number, since it is larger than the sum of its proper divisors (801623).

8817721 is a wasteful number, since it uses less digits than its factorization.

8817721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 801622.

The product of its digits is 6272, while the sum is 34.

The square root of 8817721 is about 2969.4647665867. The cubic root of 8817721 is about 206.5945137765.

The spelling of 8817721 in words is "eight million, eight hundred seventeen thousand, seven hundred twenty-one".