1221021220101 has 16 divisors (see below), whose sum is σ = 1724540738688. Its totient is φ = 765799372800.

The previous prime is 1221021220091. The next prime is 1221021220157. The reversal of 1221021220101 is 1010221201221.

It is not a de Polignac number, because 1221021220101 - 2⁶ = 1221021220037 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221021220201) 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 15 ways as a sum of consecutive naturals, for example, 5062060 + ... + 5297781.

It is an arithmetic number, because the mean of its divisors is an integer number (107783796168).

Almost surely, 2^{1221021220101} is an apocalyptic number.

It is an amenable number.

1221021220101 is a deficient number, since it is larger than the sum of its proper divisors (503519518587).

1221021220101 is a wasteful number, since it uses less digits than its factorization.

1221021220101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10362172.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221021220101 its reverse (1010221201221), we get a palindrome (2231242421322).

The spelling of 1221021220101 in words is "one trillion, two hundred twenty-one billion, twenty-one million, two hundred twenty thousand, one hundred one".