1211020209 has 24 divisors (see below), whose sum is σ = 2016847872. Its totient is φ = 685883520.

The previous prime is 1211020207. The next prime is 1211020229. The reversal of 1211020209 is 9020201121.

It is not a de Polignac number, because 1211020209 - 2¹ = 1211020207 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211020191 and 1211020200.

It is not an unprimeable number, because it can be changed into a prime (1211020207) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77937 + ... + 92174.

It is an arithmetic number, because the mean of its divisors is an integer number (84035328).

Almost surely, 2^1211020209 is an apocalyptic number.

It is an amenable number.

1211020209 is a deficient number, since it is larger than the sum of its proper divisors (805827663).

1211020209 is a wasteful number, since it uses less digits than its factorization.

1211020209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170237 (or 170234 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 1211020209 is about 34799.7156453900. The cubic root of 1211020209 is about 1065.9016394102.

The spelling of 1211020209 in words is "one billion, two hundred eleven million, twenty thousand, two hundred nine".