121212205 has 4 divisors (see below), whose sum is σ = 145454652. Its totient is φ = 96969760.

The previous prime is 121212181. The next prime is 121212209. The reversal of 121212205 is 502212121.

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 25583364 + 95628841 = 5058^2 + 9779^2 .

It is not a de Polignac number, because 121212205 - 2⁵ = 121212173 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 (121212209) 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, 12121216 + ... + 12121225.

It is an arithmetic number, because the mean of its divisors is an integer number (36363663).

Almost surely, 2^121212205 is an apocalyptic number.

It is an amenable number.

121212205 is a deficient number, since it is larger than the sum of its proper divisors (24242447).

121212205 is an equidigital number, since it uses as much as digits as its factorization.

121212205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24242446.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 121212205 is about 11009.6414564690. The cubic root of 121212205 is about 494.8977171926.

Adding to 121212205 its reverse (502212121), we get a palindrome (623424326).

The spelling of 121212205 in words is "one hundred twenty-one million, two hundred twelve thousand, two hundred five".