28000381 has 2 divisors, whose sum is σ = 28000382. Its totient is φ = 28000380.

The previous prime is 28000367. The next prime is 28000393. The reversal of 28000381 is 18300082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23863225 + 4137156 = 4885^2 + 2034^2 .

It is a cyclic number.

It is not a de Polignac number, because 28000381 - 2⁹ = 27999869 is a prime.

It is a super-2 number, since 2×28000381² = 1568042672290322, which contains 22 as substring.

It is equal to p_1741450 and since 28000381 and 1741450 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28000321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14000190 + 14000191.

It is an arithmetic number, because the mean of its divisors is an integer number (14000191).

Almost surely, 2^28000381 is an apocalyptic number.

It is an amenable number.

28000381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28000381 is an equidigital number, since it uses as much as digits as its factorization.

28000381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 28000381 is about 5291.5386231228. The cubic root of 28000381 is about 303.6602744913.

The spelling of 28000381 in words is "twenty-eight million, three hundred eighty-one", and thus it is an aban number.