28687791 has 16 divisors (see below), whose sum is σ = 41845248. Its totient is φ = 17337600.

The previous prime is 28687783. The next prime is 28687801. The reversal of 28687791 is 19778682.

It is not a de Polignac number, because 28687791 - 2³ = 28687783 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28687791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28687781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13215 + ... + 15231.

It is an arithmetic number, because the mean of its divisors is an integer number (2615328).

Almost surely, 2^28687791 is an apocalyptic number.

28687791 is a deficient number, since it is larger than the sum of its proper divisors (13157457).

28687791 is a wasteful number, since it uses less digits than its factorization.

28687791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2462.

The product of its digits is 338688, while the sum is 48.

The square root of 28687791 is about 5356.0984867719. The cubic root of 28687791 is about 306.1251677267.

The spelling of 28687791 in words is "twenty-eight million, six hundred eighty-seven thousand, seven hundred ninety-one".