1220012121221 has 4 divisors (see below), whose sum is σ = 1220018108652. Its totient is φ = 1220006133792.

The previous prime is 1220012121217. The next prime is 1220012121347. The reversal of 1220012121221 is 1221212100221.

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 401466700996 + 818545420225 = 633614^2 + 904735^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220012121221 - 2² = 1220012121217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220012121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220012111221) 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, 2676896 + ... + 3099321.

It is an arithmetic number, because the mean of its divisors is an integer number (305004527163).

Almost surely, 2^{1220012121221} is an apocalyptic number.

It is an amenable number.

1220012121221 is a deficient number, since it is larger than the sum of its proper divisors (5987431).

1220012121221 is an equidigital number, since it uses as much as digits as its factorization.

1220012121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5987430.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1220012121221 its reverse (1221212100221), we get a palindrome (2441224221442).

The spelling of 1220012121221 in words is "one trillion, two hundred twenty billion, twelve million, one hundred twenty-one thousand, two hundred twenty-one".