42439391 has 2 divisors, whose sum is σ = 42439392. Its totient is φ = 42439390.

The previous prime is 42439381. The next prime is 42439427. The reversal of 42439391 is 19393424.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42439391 is a prime.

It is a super-2 number, since 2×42439391² = 3602203816901762, which contains 22 as substring.

It is a plaindrome in base 12.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42439381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21219695 + 21219696.

It is an arithmetic number, because the mean of its divisors is an integer number (21219696).

Almost surely, 2^42439391 is an apocalyptic number.

42439391 is a deficient number, since it is larger than the sum of its proper divisors (1).

42439391 is an equidigital number, since it uses as much as digits as its factorization.

42439391 is an odious number, because the sum of its binary digits is odd.

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

The square root of 42439391 is about 6514.5522486200. The cubic root of 42439391 is about 348.8106322642.

The spelling of 42439391 in words is "forty-two million, four hundred thirty-nine thousand, three hundred ninety-one".