28405445 has 4 divisors (see below), whose sum is σ = 34086540. Its totient is φ = 22724352.

The previous prime is 28405423. The next prime is 28405451. The reversal of 28405445 is 54450482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54450482 = 2 ⋅27225241.

It can be written as a sum of positive squares in 2 ways, for example, as 19838116 + 8567329 = 4454^2 + 2927^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28405445 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2840540 + ... + 2840549.

It is an arithmetic number, because the mean of its divisors is an integer number (8521635).

Almost surely, 2^28405445 is an apocalyptic number.

It is an amenable number.

28405445 is a deficient number, since it is larger than the sum of its proper divisors (5681095).

28405445 is an equidigital number, since it uses as much as digits as its factorization.

28405445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5681094.

The product of its (nonzero) digits is 25600, while the sum is 32.

The square root of 28405445 is about 5329.6758813271. The cubic root of 28405445 is about 305.1175574784.

The spelling of 28405445 in words is "twenty-eight million, four hundred five thousand, four hundred forty-five".