42139439 has 2 divisors, whose sum is σ = 42139440. Its totient is φ = 42139438.

The previous prime is 42139429. The next prime is 42139451. The reversal of 42139439 is 93493124.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42139439 - 2²⁴ = 25362223 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_2555558 and since 42139439 and 2555558 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 42139399 and 42139408.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42139429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21069719 + 21069720.

It is an arithmetic number, because the mean of its divisors is an integer number (21069720).

Almost surely, 2^42139439 is an apocalyptic number.

42139439 is a deficient number, since it is larger than the sum of its proper divisors (1).

42139439 is an equidigital number, since it uses as much as digits as its factorization.

42139439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 35.

The square root of 42139439 is about 6491.4897365705. The cubic root of 42139439 is about 347.9869170886.

The spelling of 42139439 in words is "forty-two million, one hundred thirty-nine thousand, four hundred thirty-nine".