209483991 has 6 divisors (see below), whose sum is σ = 302588000. Its totient is φ = 139655988.

The previous prime is 209483969. The next prime is 209483993. The reversal of 209483991 is 199384902.

It is not a de Polignac number, because 209483991 - 2⁷ = 209483863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209483993) 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 5 ways as a sum of consecutive naturals, for example, 11637991 + ... + 11638008.

Almost surely, 2^209483991 is an apocalyptic number.

209483991 is a deficient number, since it is larger than the sum of its proper divisors (93104009).

209483991 is a wasteful number, since it uses less digits than its factorization.

209483991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23276005 (or 23276002 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 209483991 is about 14473.5617938364. The cubic root of 209483991 is about 593.9049519721.

The spelling of 209483991 in words is "two hundred nine million, four hundred eighty-three thousand, nine hundred ninety-one".