28108673981 has 8 divisors (see below), whose sum is σ = 28158024024. Its totient is φ = 28059359040.

The previous prime is 28108673969. The next prime is 28108674019. The reversal of 28108673981 is 18937680182.

It can be written as a sum of positive squares in 4 ways, for example, as 969076900 + 27139597081 = 31130^2 + 164741^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28108673981 - 2¹⁴ = 28108657597 is a prime.

It is a super-2 number, since 2×28108673981² (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 (28108673381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1969451 + ... + 1983671.

It is an arithmetic number, because the mean of its divisors is an integer number (3519753003).

Almost surely, 2^28108673981 is an apocalyptic number.

It is an amenable number.

28108673981 is a deficient number, since it is larger than the sum of its proper divisors (49350043).

28108673981 is a wasteful number, since it uses less digits than its factorization.

28108673981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17551.

The product of its (nonzero) digits is 1161216, while the sum is 53.

The spelling of 28108673981 in words is "twenty-eight billion, one hundred eight million, six hundred seventy-three thousand, nine hundred eighty-one".