28105687 has 4 divisors (see below), whose sum is σ = 28310976. Its totient is φ = 27900400.

The previous prime is 28105667. The next prime is 28105697. The reversal of 28105687 is 78650182.

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 28105687 - 2⁷ = 28105559 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 (28105667) 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, 102439 + ... + 102712.

It is an arithmetic number, because the mean of its divisors is an integer number (7077744).

Almost surely, 2^28105687 is an apocalyptic number.

28105687 is a deficient number, since it is larger than the sum of its proper divisors (205289).

28105687 is a wasteful number, since it uses less digits than its factorization.

28105687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205288.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 28105687 is about 5301.4796991029. The cubic root of 28105687 is about 304.0404746144.

The spelling of 28105687 in words is "twenty-eight million, one hundred five thousand, six hundred eighty-seven".