84639439 has 2 divisors, whose sum is σ = 84639440. Its totient is φ = 84639438.

The previous prime is 84639421. The next prime is 84639469. The reversal of 84639439 is 93493648.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-84639439 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84639419) 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, 42319719 + 42319720.

It is an arithmetic number, because the mean of its divisors is an integer number (42319720).

Almost surely, 2^84639439 is an apocalyptic number.

84639439 is a deficient number, since it is larger than the sum of its proper divisors (1).

84639439 is an equidigital number, since it uses as much as digits as its factorization.

84639439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 46.

The square root of 84639439 is about 9199.9695108190. The cubic root of 84639439 is about 439.0603898844.

It can be divided in two parts, 84639 and 439, that added together give a triangular number (85078 = T₄₁₂).

The spelling of 84639439 in words is "eighty-four million, six hundred thirty-nine thousand, four hundred thirty-nine".