28390549 has 4 divisors (see below), whose sum is σ = 30971520. Its totient is φ = 25809580.

The previous prime is 28390543. The next prime is 28390589. The reversal of 28390549 is 94509382.

It is a happy number.

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 28390549 - 2⁵ = 28390517 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28390543) 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, 1290469 + ... + 1290490.

It is an arithmetic number, because the mean of its divisors is an integer number (7742880).

Almost surely, 2^28390549 is an apocalyptic number.

It is an amenable number.

28390549 is a deficient number, since it is larger than the sum of its proper divisors (2580971).

28390549 is a wasteful number, since it uses less digits than its factorization.

28390549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2580970.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 28390549 is about 5328.2782397319. The cubic root of 28390549 is about 305.0642129424.

The spelling of 28390549 in words is "twenty-eight million, three hundred ninety thousand, five hundred forty-nine".