1221220021101 has 16 divisors (see below), whose sum is σ = 1666714536960. Its totient is φ = 794948681520.

The previous prime is 1221220021097. The next prime is 1221220021117. The reversal of 1221220021101 is 1011200221221.

It is not a de Polignac number, because 1221220021101 - 2² = 1221220021097 is a prime.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 1183621 + ... + 1960458.

It is an arithmetic number, because the mean of its divisors is an integer number (104169658560).

Almost surely, 2^{1221220021101} is an apocalyptic number.

It is an amenable number.

1221220021101 is a deficient number, since it is larger than the sum of its proper divisors (445494515859).

1221220021101 is a wasteful number, since it uses less digits than its factorization.

1221220021101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3147136.

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

Adding to 1221220021101 its reverse (1011200221221), we get a palindrome (2232420242322).

The spelling of 1221220021101 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, twenty-one thousand, one hundred one".