28540921181 has 4 divisors (see below), whose sum is σ = 28592162172. Its totient is φ = 28489680192.

The previous prime is 28540921177. The next prime is 28540921207. The reversal of 28540921181 is 18112904582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 832322500 + 27708598681 = 28850^2 + 166459^2 .

It is a cyclic number.

It is not a de Polignac number, because 28540921181 - 2² = 28540921177 is a prime.

It is a super-2 number, since 2×28540921181² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28540921111) 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, 25619660 + ... + 25620773.

It is an arithmetic number, because the mean of its divisors is an integer number (7148040543).

Almost surely, 2^28540921181 is an apocalyptic number.

It is an amenable number.

28540921181 is a deficient number, since it is larger than the sum of its proper divisors (51240991).

28540921181 is an equidigital number, since it uses as much as digits as its factorization.

28540921181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51240990.

The product of its (nonzero) digits is 46080, while the sum is 41.

The spelling of 28540921181 in words is "twenty-eight billion, five hundred forty million, nine hundred twenty-one thousand, one hundred eighty-one".