28640329 has 4 divisors (see below), whose sum is σ = 28658176. Its totient is φ = 28622484.

The previous prime is 28640327. The next prime is 28640347. The reversal of 28640329 is 92304682.

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, and also an emirpimes, since its reverse is a distinct semiprime: 92304682 = 2 ⋅46152341.

It is a cyclic number.

It is not a de Polignac number, because 28640329 - 2¹ = 28640327 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28640294 and 28640303.

It is not an unprimeable number, because it can be changed into a prime (28640327) 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, 6249 + ... + 9814.

It is an arithmetic number, because the mean of its divisors is an integer number (7164544).

Almost surely, 2^28640329 is an apocalyptic number.

It is an amenable number.

28640329 is a deficient number, since it is larger than the sum of its proper divisors (17847).

28640329 is a wasteful number, since it uses less digits than its factorization.

28640329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17846.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 28640329 is about 5351.6660022838. Note that the first 3 decimals coincide. The cubic root of 28640329 is about 305.9562534469.

The spelling of 28640329 in words is "twenty-eight million, six hundred forty thousand, three hundred twenty-nine".