2121000009 has 4 divisors (see below), whose sum is σ = 2828000016. Its totient is φ = 1414000004.

The previous prime is 2120999989. The next prime is 2121000023. The reversal of 2121000009 is 9000001212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2121000009 - 2⁵ = 2120999977 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2121000059) 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, 353499999 + ... + 353500004.

It is an arithmetic number, because the mean of its divisors is an integer number (707000004).

Almost surely, 2^2121000009 is an apocalyptic number.

It is an amenable number.

2121000009 is a deficient number, since it is larger than the sum of its proper divisors (707000007).

2121000009 is an equidigital number, since it uses as much as digits as its factorization.

2121000009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 707000006.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 2121000009 is about 46054.3158563885. The cubic root of 2121000009 is about 1284.8336138890.

The spelling of 2121000009 in words is "two billion, one hundred twenty-one million, nine", and thus it is an aban number.