28177021 has 2 divisors, whose sum is σ = 28177022. Its totient is φ = 28177020.

The previous prime is 28177013. The next prime is 28177027. The reversal of 28177021 is 12077182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27941796 + 235225 = 5286^2 + 485^2 .

It is a cyclic number.

It is not a de Polignac number, because 28177021 - 2³ = 28177013 is a prime.

It is equal to p_1751761 and since 28177021 and 1751761 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28177027) 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, 14088510 + 14088511.

It is an arithmetic number, because the mean of its divisors is an integer number (14088511).

Almost surely, 2^28177021 is an apocalyptic number.

It is an amenable number.

28177021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28177021 is an equidigital number, since it uses as much as digits as its factorization.

28177021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 28177021 is about 5308.2031799847. The cubic root of 28177021 is about 304.2974819143.

The spelling of 28177021 in words is "twenty-eight million, one hundred seventy-seven thousand, twenty-one".