1221211110101 has 4 divisors (see below), whose sum is σ = 1293047057772. Its totient is φ = 1149375162432.

The previous prime is 1221211110089. The next prime is 1221211110103. The reversal of 1221211110101 is 1010111121221.

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 1032530338225 + 188680771876 = 1016135^2 + 434374^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221211110101 - 2¹⁰ = 1221211109077 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 (1221211110103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35917973810 + ... + 35917973843.

It is an arithmetic number, because the mean of its divisors is an integer number (323261764443).

Almost surely, 2^{1221211110101} is an apocalyptic number.

It is an amenable number.

1221211110101 is a deficient number, since it is larger than the sum of its proper divisors (71835947671).

1221211110101 is an equidigital number, since it uses as much as digits as its factorization.

1221211110101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71835947670.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 1221211110101 its reverse (1010111121221), we get a palindrome (2231322231322).

The spelling of 1221211110101 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred ten thousand, one hundred one".