2101121209 has 16 divisors (see below), whose sum is σ = 2341797120. Its totient is φ = 1869154560.

The previous prime is 2101121207. The next prime is 2101121237. The reversal of 2101121209 is 9021211012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 2101121209 - 2¹ = 2101121207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2101121207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87499 + ... + 108895.

It is an arithmetic number, because the mean of its divisors is an integer number (146362320).

Almost surely, 2^2101121209 is an apocalyptic number.

It is an amenable number.

2101121209 is a deficient number, since it is larger than the sum of its proper divisors (240675911).

2101121209 is a wasteful number, since it uses less digits than its factorization.

2101121209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21600.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 2101121209 is about 45837.9887102390. The cubic root of 2101121209 is about 1280.8070287069.

The spelling of 2101121209 in words is "two billion, one hundred one million, one hundred twenty-one thousand, two hundred nine".