209920830 has 32 divisors (see below), whose sum is σ = 575783424. Its totient is φ = 47981856.

The previous prime is 209920813. The next prime is 209920897. The reversal of 209920830 is 38029902.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 209920791 and 209920800.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 499602 + ... + 500021.

It is an arithmetic number, because the mean of its divisors is an integer number (17993232).

Almost surely, 2^209920830 is an apocalyptic number.

209920830 is an abundant number, since it is smaller than the sum of its proper divisors (365862594).

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

209920830 is a wasteful number, since it uses less digits than its factorization.

209920830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999640.

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 209920830 is about 14488.6448641686. The cubic root of 209920830 is about 594.3174906018.

The spelling of 209920830 in words is "two hundred nine million, nine hundred twenty thousand, eight hundred thirty".