28811785 has 8 divisors (see below), whose sum is σ = 34827336. Its totient is φ = 22880640.

The previous prime is 28811779. The next prime is 28811831. The reversal of 28811785 is 58711882.

It can be written as a sum of positive squares in 4 ways, for example, as 12787776 + 16024009 = 3576^2 + 4003^2 .

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

It is not a de Polignac number, because 28811785 - 2¹⁵ = 28779017 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20346 + ... + 21715.

It is an arithmetic number, because the mean of its divisors is an integer number (4353417).

Almost surely, 2^28811785 is an apocalyptic number.

It is an amenable number.

28811785 is a deficient number, since it is larger than the sum of its proper divisors (6015551).

28811785 is a wasteful number, since it uses less digits than its factorization.

28811785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42203.

The product of its digits is 35840, while the sum is 40.

The square root of 28811785 is about 5367.6610362429. The cubic root of 28811785 is about 306.5655772404.

The spelling of 28811785 in words is "twenty-eight million, eight hundred eleven thousand, seven hundred eighty-five".