209686399947 has 40 divisors (see below), whose sum is σ = 330123932160. Its totient is φ = 132271801200.

The previous prime is 209686399939. The next prime is 209686399969. The reversal of 209686399947 is 749993686902.

It is not a de Polignac number, because 209686399947 - 2³ = 209686399939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (209686399907) 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 39 ways as a sum of consecutive naturals, for example, 1183822 + ... + 1349372.

It is an arithmetic number, because the mean of its divisors is an integer number (8253098304).

Almost surely, 2^209686399947 is an apocalyptic number.

209686399947 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

209686399947 is a deficient number, since it is larger than the sum of its proper divisors (120437532213).

209686399947 is a wasteful number, since it uses less digits than its factorization.

209686399947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166405 (or 166396 counting only the distinct ones).

The product of its (nonzero) digits is 317447424, while the sum is 72.

The spelling of 209686399947 in words is "two hundred nine billion, six hundred eighty-six million, three hundred ninety-nine thousand, nine hundred forty-seven".