2121120109 has 4 divisors (see below), whose sum is σ = 2121896700. Its totient is φ = 2120343520.

The previous prime is 2121120061. The next prime is 2121120137. The reversal of 2121120109 is 9010211212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 570493225 + 1550626884 = 23885^2 + 39378^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121120109 - 2¹⁵ = 2121087341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121160109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 384184 + ... + 389665.

It is an arithmetic number, because the mean of its divisors is an integer number (530474175).

Almost surely, 2^2121120109 is an apocalyptic number.

It is an amenable number.

2121120109 is a deficient number, since it is larger than the sum of its proper divisors (776591).

2121120109 is an equidigital number, since it uses as much as digits as its factorization.

2121120109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 776590.

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

The square root of 2121120109 is about 46055.6197331010. The cubic root of 2121120109 is about 1284.8578643375.

The spelling of 2121120109 in words is "two billion, one hundred twenty-one million, one hundred twenty thousand, one hundred nine".