8721424 has 10 divisors (see below), whose sum is σ = 16897790. Its totient is φ = 4360704.

The previous prime is 8721413. The next prime is 8721443. The reversal of 8721424 is 4241278.

It can be written as a sum of positive squares in only one way, i.e., 6411024 + 2310400 = 2532^2 + 1520^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 8721392 and 8721401.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 272529 + ... + 272560.

It is an arithmetic number, because the mean of its divisors is an integer number (1689779).

Almost surely, 2^8721424 is an apocalyptic number.

It is an amenable number.

8721424 is a deficient number, since it is larger than the sum of its proper divisors (8176366).

8721424 is a wasteful number, since it uses less digits than its factorization.

8721424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545097 (or 545091 counting only the distinct ones).

The product of its digits is 3584, while the sum is 28.

The square root of 8721424 is about 2953.2057158281. The cubic root of 8721424 is about 205.8396968243.

The spelling of 8721424 in words is "eight million, seven hundred twenty-one thousand, four hundred twenty-four".