12120809 has 4 divisors (see below), whose sum is σ = 12136260. Its totient is φ = 12105360.

The previous prime is 12120781. The next prime is 12120833. The reversal of 12120809 is 90802121.

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 2166784 + 9954025 = 1472^2 + 3155^2 .

It is a cyclic number.

It is not a de Polignac number, because 12120809 - 2¹⁶ = 12055273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12120859) 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, 6482 + ... + 8139.

It is an arithmetic number, because the mean of its divisors is an integer number (3034065).

Almost surely, 2^12120809 is an apocalyptic number.

It is an amenable number.

12120809 is a deficient number, since it is larger than the sum of its proper divisors (15451).

12120809 is an equidigital number, since it uses as much as digits as its factorization.

12120809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15450.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 12120809 is about 3481.4952247562. The cubic root of 12120809 is about 229.7085722935.

The spelling of 12120809 in words is "twelve million, one hundred twenty thousand, eight hundred nine".