2154120209 has 2 divisors, whose sum is σ = 2154120210. Its totient is φ = 2154120208.

The previous prime is 2154120187. The next prime is 2154120211. The reversal of 2154120209 is 9020214512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1082212609 + 1071907600 = 32897^2 + 32740^2 .

It is a cyclic number.

It is not a de Polignac number, because 2154120209 - 2²⁰ = 2153071633 is a prime.

Together with 2154120211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2154120289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077060104 + 1077060105.

It is an arithmetic number, because the mean of its divisors is an integer number (1077060105).

Almost surely, 2^2154120209 is an apocalyptic number.

It is an amenable number.

2154120209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2154120209 is an equidigital number, since it uses as much as digits as its factorization.

2154120209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 2154120209 is about 46412.5005682736. The cubic root of 2154120209 is about 1291.4868198151.

The spelling of 2154120209 in words is "two billion, one hundred fifty-four million, one hundred twenty thousand, two hundred nine".