42128549 has 2 divisors, whose sum is σ = 42128550. Its totient is φ = 42128548.

The previous prime is 42128477. The next prime is 42128551. The reversal of 42128549 is 94582124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42016324 + 112225 = 6482^2 + 335^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42128549 is a prime.

It is a Sophie Germain prime.

Together with 42128551, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42128579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21064274 + 21064275.

It is an arithmetic number, because the mean of its divisors is an integer number (21064275).

Almost surely, 2^42128549 is an apocalyptic number.

It is an amenable number.

42128549 is a deficient number, since it is larger than the sum of its proper divisors (1).

42128549 is an equidigital number, since it uses as much as digits as its factorization.

42128549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23040, while the sum is 35.

The square root of 42128549 is about 6490.6508918598. The cubic root of 42128549 is about 347.9569380151.

The spelling of 42128549 in words is "forty-two million, one hundred twenty-eight thousand, five hundred forty-nine".