28028397 has 4 divisors (see below), whose sum is σ = 37371200. Its totient is φ = 18685596.

The previous prime is 28028387. The next prime is 28028411. The reversal of 28028397 is 79382082.

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 not a de Polignac number, because 28028397 - 2⁴ = 28028381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28028317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4671397 + ... + 4671402.

It is an arithmetic number, because the mean of its divisors is an integer number (9342800).

Almost surely, 2^28028397 is an apocalyptic number.

It is an amenable number.

28028397 is a deficient number, since it is larger than the sum of its proper divisors (9342803).

28028397 is an equidigital number, since it uses as much as digits as its factorization.

28028397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9342802.

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 28028397 is about 5294.1852064317. The cubic root of 28028397 is about 303.7615172859.

The spelling of 28028397 in words is "twenty-eight million, twenty-eight thousand, three hundred ninety-seven".