1221220020121 has 4 divisors (see below), whose sum is σ = 1223835052752. Its totient is φ = 1218604987492.

The previous prime is 1221220020029. The next prime is 1221220020143. The reversal of 1221220020121 is 1210200221221.

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 1221220020121 - 2²³ = 1221211631513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221220020095 and 1221220020104.

It is not an unprimeable number, because it can be changed into a prime (1221220021121) 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, 1307515615 + ... + 1307516548.

It is an arithmetic number, because the mean of its divisors is an integer number (305958763188).

Almost surely, 2^{1221220020121} is an apocalyptic number.

It is an amenable number.

1221220020121 is a deficient number, since it is larger than the sum of its proper divisors (2615032631).

1221220020121 is an equidigital number, since it uses as much as digits as its factorization.

1221220020121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2615032630.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 1221220020121 its reverse (1210200221221), we get a palindrome (2431420241342).

The spelling of 1221220020121 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, twenty thousand, one hundred twenty-one".