28191487 has 4 divisors (see below), whose sum is σ = 28204696. Its totient is φ = 28178280.

The previous prime is 28191467. The next prime is 28191517. The reversal of 28191487 is 78419182.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28191487 - 2¹¹ = 28189439 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 (28191467) 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, 2589 + ... + 7942.

It is an arithmetic number, because the mean of its divisors is an integer number (7051174).

Almost surely, 2^28191487 is an apocalyptic number.

28191487 is a deficient number, since it is larger than the sum of its proper divisors (13209).

28191487 is a wasteful number, since it uses less digits than its factorization.

28191487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13208.

The product of its digits is 32256, while the sum is 40.

The square root of 28191487 is about 5309.5656131175. The cubic root of 28191487 is about 304.3495481503.

The spelling of 28191487 in words is "twenty-eight million, one hundred ninety-one thousand, four hundred eighty-seven".