209920923 has 8 divisors (see below), whose sum is σ = 310994000. Its totient is φ = 139947264.

The previous prime is 209920903. The next prime is 209920939. The reversal of 209920923 is 329029902.

It is not a de Polignac number, because 209920923 - 2²⁰ = 208872347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209920903) 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, 3887398 + ... + 3887451.

It is an arithmetic number, because the mean of its divisors is an integer number (38874250).

Almost surely, 2^209920923 is an apocalyptic number.

209920923 is a deficient number, since it is larger than the sum of its proper divisors (101073077).

209920923 is an equidigital number, since it uses as much as digits as its factorization.

209920923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7774858 (or 7774852 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 209920923 is about 14488.6480735782. The cubic root of 209920923 is about 594.3175783674.

The spelling of 209920923 in words is "two hundred nine million, nine hundred twenty thousand, nine hundred twenty-three".