28913321 has 4 divisors (see below), whose sum is σ = 28930944. Its totient is φ = 28895700.

The previous prime is 28913309. The next prime is 28913327. The reversal of 28913321 is 12331982.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28913321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28913327) 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, 6065 + ... + 9726.

It is an arithmetic number, because the mean of its divisors is an integer number (7232736).

Almost surely, 2^28913321 is an apocalyptic number.

It is an amenable number.

28913321 is a deficient number, since it is larger than the sum of its proper divisors (17623).

28913321 is a wasteful number, since it uses less digits than its factorization.

28913321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17622.

The product of its digits is 2592, while the sum is 29.

The square root of 28913321 is about 5377.1108413348. The cubic root of 28913321 is about 306.9252789889.

The spelling of 28913321 in words is "twenty-eight million, nine hundred thirteen thousand, three hundred twenty-one".