8443721 has 16 divisors (see below), whose sum is σ = 10015488. Its totient is φ = 7017600.

The previous prime is 8443717. The next prime is 8443739. The reversal of 8443721 is 1273448.

It is a cyclic number.

It is not a de Polignac number, because 8443721 - 2² = 8443717 is a prime.

It is a d-powerful number, because it can be written as 8⁵ + 4 + 4⁴ + 3⁹ + 7⁴ + 2²³ + 1 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8443711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19376 + ... + 19806.

It is an arithmetic number, because the mean of its divisors is an integer number (625968).

Almost surely, 2^8443721 is an apocalyptic number.

It is an amenable number.

8443721 is a deficient number, since it is larger than the sum of its proper divisors (1571767).

8443721 is a wasteful number, since it uses less digits than its factorization.

8443721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592.

The product of its digits is 5376, while the sum is 29.

The square root of 8443721 is about 2905.8081492074. The cubic root of 8443721 is about 203.6313427070.

The spelling of 8443721 in words is "eight million, four hundred forty-three thousand, seven hundred twenty-one".