209031820 has 24 divisors (see below), whose sum is σ = 458053344. Its totient is φ = 79977216.

The previous prime is 209031793. The next prime is 209031827. The reversal of 209031820 is 28130902.

It is not an unprimeable number, because it can be changed into a prime (209031827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226749 + ... + 227668.

It is an arithmetic number, because the mean of its divisors is an integer number (19085556).

Almost surely, 2^209031820 is an apocalyptic number.

209031820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209031820 is an abundant number, since it is smaller than the sum of its proper divisors (249021524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209031820 is a wasteful number, since it uses less digits than its factorization.

209031820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454449 (or 454447 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 209031820 is about 14457.9327706280. The cubic root of 209031820 is about 593.4773297212.

The spelling of 209031820 in words is "two hundred nine million, thirty-one thousand, eight hundred twenty".