208957349989 has 2 divisors, whose sum is σ = 208957349990. Its totient is φ = 208957349988.

The previous prime is 208957349917. The next prime is 208957350023. The reversal of 208957349989 is 989943759802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204218129025 + 4739220964 = 451905^2 + 68842^2 .

It is a cyclic number.

It is not a de Polignac number, because 208957349989 - 2¹⁵ = 208957317221 is a prime.

It is a super-3 number, since 3×208957349989³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208957349189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104478674994 + 104478674995.

It is an arithmetic number, because the mean of its divisors is an integer number (104478674995).

Almost surely, 2^208957349989 is an apocalyptic number.

It is an amenable number.

208957349989 is a deficient number, since it is larger than the sum of its proper divisors (1).

208957349989 is an equidigital number, since it uses as much as digits as its factorization.

208957349989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 352719360, while the sum is 73.

The spelling of 208957349989 in words is "two hundred eight billion, nine hundred fifty-seven million, three hundred forty-nine thousand, nine hundred eighty-nine".