28716518381 has 2 divisors, whose sum is σ = 28716518382. Its totient is φ = 28716518380.

The previous prime is 28716518377. The next prime is 28716518399. The reversal of 28716518381 is 18381561782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27858614281 + 857904100 = 166909^2 + 29290^2 .

It is a cyclic number.

It is not a de Polignac number, because 28716518381 - 2² = 28716518377 is a prime.

It is a super-2 number, since 2×28716518381² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28716518681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14358259190 + 14358259191.

It is an arithmetic number, because the mean of its divisors is an integer number (14358259191).

Almost surely, 2^28716518381 is an apocalyptic number.

It is an amenable number.

28716518381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28716518381 is an equidigital number, since it uses as much as digits as its factorization.

28716518381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 645120, while the sum is 50.

The spelling of 28716518381 in words is "twenty-eight billion, seven hundred sixteen million, five hundred eighteen thousand, three hundred eighty-one".