28096921 has 4 divisors (see below), whose sum is σ = 28573200. Its totient is φ = 27620644.

The previous prime is 28096907. The next prime is 28096927. The reversal of 28096921 is 12969082.

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 not a de Polignac number, because 28096921 - 2⁵ = 28096889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28096927) 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, 238051 + ... + 238168.

It is an arithmetic number, because the mean of its divisors is an integer number (7143300).

Almost surely, 2^28096921 is an apocalyptic number.

It is an amenable number.

28096921 is a deficient number, since it is larger than the sum of its proper divisors (476279).

28096921 is an equidigital number, since it uses as much as digits as its factorization.

28096921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476278.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 28096921 is about 5300.6528843153. The cubic root of 28096921 is about 304.0088618435.

It can be divided in two parts, 2809 and 6921, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 28096921 in words is "twenty-eight million, ninety-six thousand, nine hundred twenty-one".