28576621681 has 4 divisors (see below), whose sum is σ = 28577095792. Its totient is φ = 28576147572.

The previous prime is 28576621657. The next prime is 28576621691. The reversal of 28576621681 is 18612667582.

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 a cyclic number.

It is not a de Polignac number, because 28576621681 - 2⁹ = 28576621169 is a prime.

It is a super-2 number, since 2×28576621681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28576621651) 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, 130755 + ... + 272488.

It is an arithmetic number, because the mean of its divisors is an integer number (7144273948).

Almost surely, 2^28576621681 is an apocalyptic number.

It is an amenable number.

28576621681 is a deficient number, since it is larger than the sum of its proper divisors (474111).

28576621681 is an equidigital number, since it uses as much as digits as its factorization.

28576621681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474110.

The product of its digits is 1935360, while the sum is 52.

The spelling of 28576621681 in words is "twenty-eight billion, five hundred seventy-six million, six hundred twenty-one thousand, six hundred eighty-one".