28108769281 has 4 divisors (see below), whose sum is σ = 28114099200. Its totient is φ = 28103439364.

The previous prime is 28108769267. The next prime is 28108769369. The reversal of 28108769281 is 18296780182.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18296780182 = 2 ⋅9148390091.

It is a cyclic number.

It is not a de Polignac number, because 28108769281 - 2¹³ = 28108761089 is a prime.

It is a super-2 number, since 2×28108769281² (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 (28108769581) 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, 2657041 + ... + 2667598.

It is an arithmetic number, because the mean of its divisors is an integer number (7028524800).

Almost surely, 2^28108769281 is an apocalyptic number.

It is an amenable number.

28108769281 is a deficient number, since it is larger than the sum of its proper divisors (5329919).

28108769281 is an equidigital number, since it uses as much as digits as its factorization.

28108769281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5329918.

The product of its (nonzero) digits is 774144, while the sum is 52.

The spelling of 28108769281 in words is "twenty-eight billion, one hundred eight million, seven hundred sixty-nine thousand, two hundred eighty-one".