28305405 has 12 divisors (see below), whose sum is σ = 49062780. Its totient is φ = 15096192.

The previous prime is 28305397. The next prime is 28305413. The reversal of 28305405 is 50450382.

It is an interprime number because it is at equal distance from previous prime (28305397) and next prime (28305413).

It can be written as a sum of positive squares in 2 ways, for example, as 13351716 + 14953689 = 3654^2 + 3867^2 .

It is not a de Polignac number, because 28305405 - 2³ = 28305397 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 314460 + ... + 314549.

It is an arithmetic number, because the mean of its divisors is an integer number (4088565).

Almost surely, 2^28305405 is an apocalyptic number.

It is an amenable number.

28305405 is a deficient number, since it is larger than the sum of its proper divisors (20757375).

28305405 is a wasteful number, since it uses less digits than its factorization.

28305405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629020 (or 629017 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 28305405 is about 5320.2824173158. The cubic root of 28305405 is about 304.7589423792.

Adding to 28305405 its reverse (50450382), we get a palindrome (78755787).

The spelling of 28305405 in words is "twenty-eight million, three hundred five thousand, four hundred five".