28891187 has 8 divisors (see below), whose sum is σ = 31227504. Its totient is φ = 26571168.

The previous prime is 28891171. The next prime is 28891189. The reversal of 28891187 is 78119882.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28891187 - 2⁴ = 28891171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28891189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 248 + ... + 7605.

It is an arithmetic number, because the mean of its divisors is an integer number (3903438).

Almost surely, 2^28891187 is an apocalyptic number.

28891187 is a deficient number, since it is larger than the sum of its proper divisors (2336317).

28891187 is a wasteful number, since it uses less digits than its factorization.

28891187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8149.

The product of its digits is 64512, while the sum is 44.

The square root of 28891187 is about 5375.0522788155. The cubic root of 28891187 is about 306.8469388770.

It can be divided in two parts, 2889 and 1187, that multiplied together give a palindrome (3429243).

The spelling of 28891187 in words is "twenty-eight million, eight hundred ninety-one thousand, one hundred eighty-seven".