209239983 has 24 divisors (see below), whose sum is σ = 314188560. Its totient is φ = 137613600.

The previous prime is 209239957. The next prime is 209239991. The reversal of 209239983 is 389932902.

It is not a de Polignac number, because 209239983 - 2²² = 205045679 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209239903) 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 in 23 ways as a sum of consecutive naturals, for example, 755241 + ... + 755517.

It is an arithmetic number, because the mean of its divisors is an integer number (13091190).

Almost surely, 2^209239983 is an apocalyptic number.

209239983 is a deficient number, since it is larger than the sum of its proper divisors (104948577).

209239983 is an equidigital number, since it uses as much as digits as its factorization.

209239983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664 (or 381 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 209239983 is about 14465.1298991748. The cubic root of 209239983 is about 593.6742678958.

The spelling of 209239983 in words is "two hundred nine million, two hundred thirty-nine thousand, nine hundred eighty-three".