42138559 has 2 divisors, whose sum is σ = 42138560. Its totient is φ = 42138558.

The previous prime is 42138557. The next prime is 42138587. The reversal of 42138559 is 95583124.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42138559 - 2¹ = 42138557 is a prime.

Together with 42138557, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42138557) 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, 21069279 + 21069280.

It is an arithmetic number, because the mean of its divisors is an integer number (21069280).

Almost surely, 2^42138559 is an apocalyptic number.

42138559 is a deficient number, since it is larger than the sum of its proper divisors (1).

42138559 is an equidigital number, since it uses as much as digits as its factorization.

42138559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43200, while the sum is 37.

The square root of 42138559 is about 6491.4219551651. The cubic root of 42138559 is about 347.9844947291.

It can be divided in two parts, 42 and 138559, that added together give a triangular number (138601 = T₅₂₆).

The spelling of 42138559 in words is "forty-two million, one hundred thirty-eight thousand, five hundred fifty-nine".