28540581 has 4 divisors (see below), whose sum is σ = 38054112. Its totient is φ = 19027052.

The previous prime is 28540573. The next prime is 28540607. The reversal of 28540581 is 18504582.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28540581 - 2³ = 28540573 is a prime.

It is a super-2 number, since 2×28540581² = 1629129527635122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28540511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4756761 + ... + 4756766.

It is an arithmetic number, because the mean of its divisors is an integer number (9513528).

Almost surely, 2^28540581 is an apocalyptic number.

It is an amenable number.

28540581 is a deficient number, since it is larger than the sum of its proper divisors (9513531).

28540581 is an equidigital number, since it uses as much as digits as its factorization.

28540581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9513530.

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 28540581 is about 5342.3385328899. The cubic root of 28540581 is about 305.6006473961.

The spelling of 28540581 in words is "twenty-eight million, five hundred forty thousand, five hundred eighty-one".