28264561 has 4 divisors (see below), whose sum is σ = 30438772. Its totient is φ = 26090352.

The previous prime is 28264519. The next prime is 28264573. The reversal of 28264561 is 16546282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18870336 + 9394225 = 4344^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 28264561 - 2⁷ = 28264433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28264501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1087086 + ... + 1087111.

It is an arithmetic number, because the mean of its divisors is an integer number (7609693).

Almost surely, 2^28264561 is an apocalyptic number.

It is an amenable number.

28264561 is a deficient number, since it is larger than the sum of its proper divisors (2174211).

28264561 is a wasteful number, since it uses less digits than its factorization.

28264561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2174210.

The product of its digits is 23040, while the sum is 34.

The square root of 28264561 is about 5316.4425135611. The cubic root of 28264561 is about 304.6122852746.

The spelling of 28264561 in words is "twenty-eight million, two hundred sixty-four thousand, five hundred sixty-one".