28587813 has 4 divisors (see below), whose sum is σ = 38117088. Its totient is φ = 19058540.

The previous prime is 28587787. The next prime is 28587817. The reversal of 28587813 is 31878582.

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 28587813 - 2¹² = 28583717 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28587817) 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 3 ways as a sum of consecutive naturals, for example, 4764633 + ... + 4764638.

It is an arithmetic number, because the mean of its divisors is an integer number (9529272).

Almost surely, 2^28587813 is an apocalyptic number.

It is an amenable number.

28587813 is a deficient number, since it is larger than the sum of its proper divisors (9529275).

28587813 is an equidigital number, since it uses as much as digits as its factorization.

28587813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9529274.

The product of its digits is 107520, while the sum is 42.

The square root of 28587813 is about 5346.7572415437. The cubic root of 28587813 is about 305.7691346776.

The spelling of 28587813 in words is "twenty-eight million, five hundred eighty-seven thousand, eight hundred thirteen".