7821328 has 10 divisors (see below), whose sum is σ = 15153854. Its totient is φ = 3910656.

The previous prime is 7821323. The next prime is 7821353. The reversal of 7821328 is 8231287.

It can be written as a sum of positive squares in only one way, i.e., 7225344 + 595984 = 2688^2 + 772^2 .

It is a super-2 number, since 2×7821328² = 122346343367168, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 7821328.

It is not an unprimeable number, because it can be changed into a prime (7821323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 244401 + ... + 244432.

Almost surely, 2^7821328 is an apocalyptic number.

It is an amenable number.

7821328 is a deficient number, since it is larger than the sum of its proper divisors (7332526).

7821328 is a wasteful number, since it uses less digits than its factorization.

7821328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488841 (or 488835 counting only the distinct ones).

The product of its digits is 5376, while the sum is 31.

The square root of 7821328 is about 2796.6637266572. The cubic root of 7821328 is about 198.4998424370.

The spelling of 7821328 in words is "seven million, eight hundred twenty-one thousand, three hundred twenty-eight".