208394639 has 4 divisors (see below), whose sum is σ = 208819560. Its totient is φ = 207969720.

The previous prime is 208394611. The next prime is 208394689. The reversal of 208394639 is 936493802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936493802 = 2 ⋅468246901.

It is a cyclic number.

It is not a de Polignac number, because 208394639 - 2¹² = 208390543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 208394639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208394689) 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 in 3 ways as a sum of consecutive naturals, for example, 211724 + ... + 212705.

It is an arithmetic number, because the mean of its divisors is an integer number (52204890).

Almost surely, 2^208394639 is an apocalyptic number.

208394639 is a deficient number, since it is larger than the sum of its proper divisors (424921).

208394639 is an equidigital number, since it uses as much as digits as its factorization.

208394639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424920.

The product of its (nonzero) digits is 279936, while the sum is 44.

The square root of 208394639 is about 14435.8802641197. The cubic root of 208394639 is about 592.8736937696.

The spelling of 208394639 in words is "two hundred eight million, three hundred ninety-four thousand, six hundred thirty-nine".