28308312781 has 12 divisors (see below), whose sum is σ = 34663241280. Its totient is φ = 22987200600.

The previous prime is 28308312779. The next prime is 28308312787. The reversal of 28308312781 is 18721380382.

It is not a de Polignac number, because 28308312781 - 2¹ = 28308312779 is a prime.

It is a super-2 number, since 2×28308312781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28308312787) 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 11 ways as a sum of consecutive naturals, for example, 15202245 + ... + 15204106.

It is an arithmetic number, because the mean of its divisors is an integer number (2888603440).

Almost surely, 2^28308312781 is an apocalyptic number.

It is an amenable number.

28308312781 is a deficient number, since it is larger than the sum of its proper divisors (6354928499).

28308312781 is a wasteful number, since it uses less digits than its factorization.

28308312781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30406384 (or 30406377 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 28308312781 in words is "twenty-eight billion, three hundred eight million, three hundred twelve thousand, seven hundred eighty-one".