28530681 has 4 divisors (see below), whose sum is σ = 38040912. Its totient is φ = 19020452.

The previous prime is 28530679. The next prime is 28530683. The reversal of 28530681 is 18603582.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (28530679) and next prime (28530683).

It is a cyclic number.

It is not a de Polignac number, because 28530681 - 2¹ = 28530679 is a prime.

It is a super-2 number, since 2×28530681² = 1627999516647522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28530683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4755111 + ... + 4755116.

It is an arithmetic number, because the mean of its divisors is an integer number (9510228).

Almost surely, 2^28530681 is an apocalyptic number.

It is an amenable number.

28530681 is a deficient number, since it is larger than the sum of its proper divisors (9510231).

28530681 is an equidigital number, since it uses as much as digits as its factorization.

28530681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9510230.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 28530681 is about 5341.4118920001. The cubic root of 28530681 is about 305.5653082850.

The spelling of 28530681 in words is "twenty-eight million, five hundred thirty thousand, six hundred eighty-one".