28181897 has 2 divisors, whose sum is σ = 28181898. Its totient is φ = 28181896.

The previous prime is 28181891. The next prime is 28181911. The reversal of 28181897 is 79818182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17397241 + 10784656 = 4171^2 + 3284^2 .

It is a cyclic number.

It is not a de Polignac number, because 28181897 - 2¹² = 28177801 is a prime.

It is not a weakly prime, because it can be changed into another prime (28181891) 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, 14090948 + 14090949.

It is an arithmetic number, because the mean of its divisors is an integer number (14090949).

Almost surely, 2^28181897 is an apocalyptic number.

It is an amenable number.

28181897 is a deficient number, since it is larger than the sum of its proper divisors (1).

28181897 is an equidigital number, since it uses as much as digits as its factorization.

28181897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 44.

The square root of 28181897 is about 5308.6624492427. The cubic root of 28181897 is about 304.3150336745.

The spelling of 28181897 in words is "twenty-eight million, one hundred eighty-one thousand, eight hundred ninety-seven".