28067911681 has 2 divisors, whose sum is σ = 28067911682. Its totient is φ = 28067911680.

The previous prime is 28067911661. The next prime is 28067911699. The reversal of 28067911681 is 18611976082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15446512656 + 12621399025 = 124284^2 + 112345^2 .

It is a cyclic number.

It is not a de Polignac number, because 28067911681 - 2⁹ = 28067911169 is a prime.

It is a super-2 number, since 2×28067911681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28067911621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14033955840 + 14033955841.

It is an arithmetic number, because the mean of its divisors is an integer number (14033955841).

Almost surely, 2^28067911681 is an apocalyptic number.

It is an amenable number.

28067911681 is a deficient number, since it is larger than the sum of its proper divisors (1).

28067911681 is an equidigital number, since it uses as much as digits as its factorization.

28067911681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 49.

The spelling of 28067911681 in words is "twenty-eight billion, sixty-seven million, nine hundred eleven thousand, six hundred eighty-one".