28178081 has 2 divisors, whose sum is σ = 28178082. Its totient is φ = 28178080.

The previous prime is 28178071. The next prime is 28178089. The reversal of 28178081 is 18087182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15928081 + 12250000 = 3991^2 + 3500^2 .

It is a cyclic number.

It is not a de Polignac number, because 28178081 - 2²² = 23983777 is a prime.

It is a super-2 number, since 2×28178081² = 1588008497685122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28178089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14089040 + 14089041.

It is an arithmetic number, because the mean of its divisors is an integer number (14089041).

Almost surely, 2^28178081 is an apocalyptic number.

It is an amenable number.

28178081 is a deficient number, since it is larger than the sum of its proper divisors (1).

28178081 is an equidigital number, since it uses as much as digits as its factorization.

28178081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 28178081 is about 5308.3030245079. The cubic root of 28178081 is about 304.3012976866.

The spelling of 28178081 in words is "twenty-eight million, one hundred seventy-eight thousand, eighty-one".