28308178081 has 4 divisors (see below), whose sum is σ = 28312486164. Its totient is φ = 28303870000.

The previous prime is 28308178037. The next prime is 28308178097. The reversal of 28308178081 is 18087180382.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18087180382 = 2 ⋅9043590191.

It can be written as a sum of positive squares in 2 ways, for example, as 21017750625 + 7290427456 = 144975^2 + 85384^2 .

It is a cyclic number.

It is not a de Polignac number, because 28308178081 - 2¹⁹ = 28307653793 is a prime.

It is a super-2 number, since 2×28308178081² (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 (28308178021) 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, 2144170 + ... + 2157331.

It is an arithmetic number, because the mean of its divisors is an integer number (7078121541).

Almost surely, 2^28308178081 is an apocalyptic number.

It is an amenable number.

28308178081 is a deficient number, since it is larger than the sum of its proper divisors (4308083).

28308178081 is an equidigital number, since it uses as much as digits as its factorization.

28308178081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4308082.

The product of its (nonzero) digits is 172032, while the sum is 46.

The spelling of 28308178081 in words is "twenty-eight billion, three hundred eight million, one hundred seventy-eight thousand, eighty-one".