42123509 has 2 divisors, whose sum is σ = 42123510. Its totient is φ = 42123508.

The previous prime is 42123493. The next prime is 42123559. The reversal of 42123509 is 90532124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28654609 + 13468900 = 5353^2 + 3670^2 .

It is a cyclic number.

It is not a de Polignac number, because 42123509 - 2⁴ = 42123493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42123559) 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, 21061754 + 21061755.

It is an arithmetic number, because the mean of its divisors is an integer number (21061755).

Almost surely, 2^42123509 is an apocalyptic number.

It is an amenable number.

42123509 is a deficient number, since it is larger than the sum of its proper divisors (1).

42123509 is an equidigital number, since it uses as much as digits as its factorization.

42123509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 42123509 is about 6490.2626295089. The cubic root of 42123509 is about 347.9430616538.

The spelling of 42123509 in words is "forty-two million, one hundred twenty-three thousand, five hundred nine".