28085381 has 2 divisors, whose sum is σ = 28085382. Its totient is φ = 28085380.

The previous prime is 28085371. The next prime is 28085383. The reversal of 28085381 is 18358082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27772900 + 312481 = 5270^2 + 559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28085381 is a prime.

It is a super-2 number, since 2×28085381² = 1577577251830322, which contains 22 as substring.

Together with 28085383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28085383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14042690 + 14042691.

It is an arithmetic number, because the mean of its divisors is an integer number (14042691).

Almost surely, 2^28085381 is an apocalyptic number.

It is an amenable number.

28085381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28085381 is an equidigital number, since it uses as much as digits as its factorization.

28085381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 28085381 is about 5299.5642273681. The cubic root of 28085381 is about 303.9672351865.

The spelling of 28085381 in words is "twenty-eight million, eighty-five thousand, three hundred eighty-one".