28678684681 has 2 divisors, whose sum is σ = 28678684682. Its totient is φ = 28678684680.

The previous prime is 28678684679. The next prime is 28678684703. The reversal of 28678684681 is 18648687682.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28676374281 + 2310400 = 169341^2 + 1520^2 .

It is a cyclic number.

It is not a de Polignac number, because 28678684681 - 2¹ = 28678684679 is a prime.

It is a super-2 number, since 2×28678684681² (a number of 22 digits) contains 22 as substring.

Together with 28678684679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (28678684651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14339342340 + 14339342341.

It is an arithmetic number, because the mean of its divisors is an integer number (14339342341).

Almost surely, 2^28678684681 is an apocalyptic number.

It is an amenable number.

28678684681 is a deficient number, since it is larger than the sum of its proper divisors (1).

28678684681 is an equidigital number, since it uses as much as digits as its factorization.

28678684681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49545216, while the sum is 64.

The spelling of 28678684681 in words is "twenty-eight billion, six hundred seventy-eight million, six hundred eighty-four thousand, six hundred eighty-one".