28736939281 has 4 divisors (see below), whose sum is σ = 30427347492. Its totient is φ = 27046531072.

The previous prime is 28736939279. The next prime is 28736939311. The reversal of 28736939281 is 18293963782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18293963782 = 2 ⋅9146981891.

It can be written as a sum of positive squares in 2 ways, for example, as 11990250000 + 16746689281 = 109500^2 + 129409^2 .

It is not a de Polignac number, because 28736939281 - 2¹ = 28736939279 is a prime.

It is a super-2 number, since 2×28736939281² (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 (28736939081) 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, 845204080 + ... + 845204113.

It is an arithmetic number, because the mean of its divisors is an integer number (7606836873).

Almost surely, 2^28736939281 is an apocalyptic number.

It is an amenable number.

28736939281 is a deficient number, since it is larger than the sum of its proper divisors (1690408211).

28736939281 is a wasteful number, since it uses less digits than its factorization.

28736939281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1690408210.

The product of its digits is 7838208, while the sum is 58.

The spelling of 28736939281 in words is "twenty-eight billion, seven hundred thirty-six million, nine hundred thirty-nine thousand, two hundred eighty-one".