28591481 has 4 divisors (see below), whose sum is σ = 28603764. Its totient is φ = 28579200.

The previous prime is 28591471. The next prime is 28591483. The reversal of 28591481 is 18419582.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2835856 + 25755625 = 1684^2 + 5075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28591481 is a prime.

It is a super-2 number, since 2×28591481² = 1634945571546722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28591483) 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, 1460 + ... + 7701.

It is an arithmetic number, because the mean of its divisors is an integer number (7150941).

Almost surely, 2^28591481 is an apocalyptic number.

It is an amenable number.

28591481 is a deficient number, since it is larger than the sum of its proper divisors (12283).

28591481 is an equidigital number, since it uses as much as digits as its factorization.

28591481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12282.

The product of its digits is 23040, while the sum is 38.

The square root of 28591481 is about 5347.1002421873. The cubic root of 28591481 is about 305.7822114995.

The spelling of 28591481 in words is "twenty-eight million, five hundred ninety-one thousand, four hundred eighty-one".