28170997 has 2 divisors, whose sum is σ = 28170998. Its totient is φ = 28170996.

The previous prime is 28170979. The next prime is 28171007. The reversal of 28170997 is 79907182.

It is a happy number.

Together with previous prime (28170979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23126481 + 5044516 = 4809^2 + 2246^2 .

It is a cyclic number.

It is not a de Polignac number, because 28170997 - 2⁷ = 28170869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28170917) 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, 14085498 + 14085499.

It is an arithmetic number, because the mean of its divisors is an integer number (14085499).

Almost surely, 2^28170997 is an apocalyptic number.

It is an amenable number.

28170997 is a deficient number, since it is larger than the sum of its proper divisors (1).

28170997 is an equidigital number, since it uses as much as digits as its factorization.

28170997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 28170997 is about 5307.6357260083. The cubic root of 28170997 is about 304.2757949910.

The spelling of 28170997 in words is "twenty-eight million, one hundred seventy thousand, nine hundred ninety-seven".