395216639 has 2 divisors, whose sum is σ = 395216640. Its totient is φ = 395216638.

The previous prime is 395216617. The next prime is 395216711. The reversal of 395216639 is 936612593.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-395216639 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 395216639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (395212639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197608319 + 197608320.

It is an arithmetic number, because the mean of its divisors is an integer number (197608320).

Almost surely, 2^395216639 is an apocalyptic number.

395216639 is a deficient number, since it is larger than the sum of its proper divisors (1).

395216639 is an equidigital number, since it uses as much as digits as its factorization.

395216639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 262440, while the sum is 44.

The square root of 395216639 is about 19880.0563127975. The cubic root of 395216639 is about 733.8575052478.

The spelling of 395216639 in words is "three hundred ninety-five million, two hundred sixteen thousand, six hundred thirty-nine".