28132768581 has 4 divisors (see below), whose sum is σ = 37510358112. Its totient is φ = 18755179052.

The previous prime is 28132768549. The next prime is 28132768607. The reversal of 28132768581 is 18586723182.

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 28132768581 - 2⁵ = 28132768549 is a prime.

It is a super-2 number, since 2×28132768581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28132768541) 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, 4688794761 + ... + 4688794766.

It is an arithmetic number, because the mean of its divisors is an integer number (9377589528).

Almost surely, 2^28132768581 is an apocalyptic number.

It is an amenable number.

28132768581 is a deficient number, since it is larger than the sum of its proper divisors (9377589531).

28132768581 is an equidigital number, since it uses as much as digits as its factorization.

28132768581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9377589530.

The product of its digits is 1290240, while the sum is 51.

The spelling of 28132768581 in words is "twenty-eight billion, one hundred thirty-two million, seven hundred sixty-eight thousand, five hundred eighty-one".