1211220011221 has 4 divisors (see below), whose sum is σ = 1321330921344. Its totient is φ = 1101109101100.

The previous prime is 1211220011203. The next prime is 1211220011257. The reversal of 1211220011221 is 1221100221121.

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 1211220011221 - 2¹⁵ = 1211219978453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211220011195 and 1211220011204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211220011321) 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, 55055455045 + ... + 55055455066.

It is an arithmetic number, because the mean of its divisors is an integer number (330332730336).

Almost surely, 2^{1211220011221} is an apocalyptic number.

1211220011221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211220011221 is a deficient number, since it is larger than the sum of its proper divisors (110110910123).

1211220011221 is a wasteful number, since it uses less digits than its factorization.

1211220011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110110910122.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1211220011221 its reverse (1221100221121), we get a palindrome (2432320232342).

The spelling of 1211220011221 in words is "one trillion, two hundred eleven billion, two hundred twenty million, eleven thousand, two hundred twenty-one".