28778171 has 2 divisors, whose sum is σ = 28778172. Its totient is φ = 28778170.

The previous prime is 28778111. The next prime is 28778213. The reversal of 28778171 is 17187782.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28778171 - 2¹⁸ = 28516027 is a prime.

It is a super-2 number, since 2×28778171² = 1656366252210482, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28778111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14389085 + 14389086.

It is an arithmetic number, because the mean of its divisors is an integer number (14389086).

Almost surely, 2^28778171 is an apocalyptic number.

28778171 is a deficient number, since it is larger than the sum of its proper divisors (1).

28778171 is an equidigital number, since it uses as much as digits as its factorization.

28778171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43904, while the sum is 41.

The square root of 28778171 is about 5364.5289634785. The cubic root of 28778171 is about 306.4463100099.

The spelling of 28778171 in words is "twenty-eight million, seven hundred seventy-eight thousand, one hundred seventy-one".