121220221 has 4 divisors (see below), whose sum is σ = 122470012. Its totient is φ = 119970432.

The previous prime is 121220213. The next prime is 121220243. The reversal of 121220221 is 122022121.

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 54552996 + 66667225 = 7386^2 + 8165^2 .

It is a cyclic number.

It is not a de Polignac number, because 121220221 - 2³ = 121220213 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 (121220201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 624750 + ... + 624943.

It is an arithmetic number, because the mean of its divisors is an integer number (30617503).

Almost surely, 2^121220221 is an apocalyptic number.

It is an amenable number.

121220221 is a deficient number, since it is larger than the sum of its proper divisors (1249791).

121220221 is an equidigital number, since it uses as much as digits as its factorization.

121220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1249790.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 121220221 is about 11010.0054950032. The cubic root of 121220221 is about 494.9086264698.

Adding to 121220221 its reverse (122022121), we get a palindrome (243242342).

The spelling of 121220221 in words is "one hundred twenty-one million, two hundred twenty thousand, two hundred twenty-one".