28309785 has 16 divisors (see below), whose sum is σ = 51766656. Its totient is φ = 12941568.

The previous prime is 28309783. The next prime is 28309823. The reversal of 28309785 is 58790382.

It is not a de Polignac number, because 28309785 - 2¹ = 28309783 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28309783) 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, 134704 + ... + 134913.

It is an arithmetic number, because the mean of its divisors is an integer number (3235416).

Almost surely, 2^28309785 is an apocalyptic number.

It is an amenable number.

28309785 is a deficient number, since it is larger than the sum of its proper divisors (23456871).

28309785 is a wasteful number, since it uses less digits than its factorization.

28309785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269632.

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 28309785 is about 5320.6940336764. The cubic root of 28309785 is about 304.7746611123.

The spelling of 28309785 in words is "twenty-eight million, three hundred nine thousand, seven hundred eighty-five".