8393721 has 16 divisors (see below), whose sum is σ = 12841344. Its totient is φ = 4777344.

The previous prime is 8393717. The next prime is 8393741. The reversal of 8393721 is 1273938.

It is not a de Polignac number, because 8393721 - 2² = 8393717 is a prime.

It is an Ulam number.

It is a d-powerful number, because it can be written as 8³ + 3 + 9 + 3⁷ + 7⁴ + 2²³ + 1 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8393711) 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, 5935 + ... + 7211.

It is an arithmetic number, because the mean of its divisors is an integer number (802584).

Almost surely, 2^8393721 is an apocalyptic number.

It is an amenable number.

8393721 is a deficient number, since it is larger than the sum of its proper divisors (4447623).

8393721 is a wasteful number, since it uses less digits than its factorization.

8393721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600.

The product of its digits is 9072, while the sum is 33.

The square root of 8393721 is about 2897.1919163217. The cubic root of 8393721 is about 203.2286083189.

It can be divided in two parts, 839 and 3721, that added together give a triangular number (4560 = T₉₅).

The spelling of 8393721 in words is "eight million, three hundred ninety-three thousand, seven hundred twenty-one".