209021139 has 12 divisors (see below), whose sum is σ = 302045016. Its totient is φ = 139289472.

The previous prime is 209021081. The next prime is 209021143. The reversal of 209021139 is 931120902.

It is not a de Polignac number, because 209021139 - 2¹⁹ = 208496851 is a prime.

It is not an unprimeable number, because it can be changed into a prime (209021149) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37987 + ... + 43139.

It is an arithmetic number, because the mean of its divisors is an integer number (25170418).

Almost surely, 2^209021139 is an apocalyptic number.

209021139 is a deficient number, since it is larger than the sum of its proper divisors (93023877).

209021139 is a wasteful number, since it uses less digits than its factorization.

209021139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9666 (or 9663 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 209021139 is about 14457.5633839178. The cubic root of 209021139 is about 593.4672211496.

The spelling of 209021139 in words is "two hundred nine million, twenty-one thousand, one hundred thirty-nine".