42168521 has 2 divisors, whose sum is σ = 42168522. Its totient is φ = 42168520.

The previous prime is 42168491. The next prime is 42168547. The reversal of 42168521 is 12586124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41731600 + 436921 = 6460^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 42168521 - 2⁶ = 42168457 is a prime.

It is not a weakly prime, because it can be changed into another prime (42168121) 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, 21084260 + 21084261.

It is an arithmetic number, because the mean of its divisors is an integer number (21084261).

Almost surely, 2^42168521 is an apocalyptic number.

It is an amenable number.

42168521 is a deficient number, since it is larger than the sum of its proper divisors (1).

42168521 is an equidigital number, since it uses as much as digits as its factorization.

42168521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 29.

The square root of 42168521 is about 6493.7293599287. The cubic root of 42168521 is about 348.0669516007.

The spelling of 42168521 in words is "forty-two million, one hundred sixty-eight thousand, five hundred twenty-one".