1221011212101 has 16 divisors (see below), whose sum is σ = 1628993602944. Its totient is φ = 813518302464.

The previous prime is 1221011212093. The next prime is 1221011212159. The reversal of 1221011212101 is 1012121101221.

It is a happy number.

It is not a de Polignac number, because 1221011212101 - 2³ = 1221011212093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011219101) 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, 39128161 + ... + 39159353.

It is an arithmetic number, because the mean of its divisors is an integer number (101812100184).

Almost surely, 2^{1221011212101} is an apocalyptic number.

It is an amenable number.

1221011212101 is a deficient number, since it is larger than the sum of its proper divisors (407982390843).

1221011212101 is a wasteful number, since it uses less digits than its factorization.

1221011212101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38620.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221011212101 its reverse (1012121101221), we get a palindrome (2233132313322).

The spelling of 1221011212101 in words is "one trillion, two hundred twenty-one billion, eleven million, two hundred twelve thousand, one hundred one".