28705945 has 16 divisors (see below), whose sum is σ = 37367568. Its totient is φ = 21084160.

The previous prime is 28705933. The next prime is 28705951. The reversal of 28705945 is 54950782.

It can be written as a sum of positive squares in 8 ways, for example, as 541696 + 28164249 = 736^2 + 5307^2 .

It is not a de Polignac number, because 28705945 - 2²¹ = 26608793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28705898 and 28705907.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 634 + ... + 7603.

It is an arithmetic number, because the mean of its divisors is an integer number (2335473).

Almost surely, 2^28705945 is an apocalyptic number.

It is an amenable number.

28705945 is a deficient number, since it is larger than the sum of its proper divisors (8661623).

28705945 is a wasteful number, since it uses less digits than its factorization.

28705945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8300.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 28705945 is about 5357.7929224635. The cubic root of 28705945 is about 306.1897274139.

The spelling of 28705945 in words is "twenty-eight million, seven hundred five thousand, nine hundred forty-five".