1221020121101 has 12 divisors (see below), whose sum is σ = 1342163670876. Its totient is φ = 1109976405120.

The previous prime is 1221020121049. The next prime is 1221020121109. The reversal of 1221020121101 is 1011210201221.

It can be written as a sum of positive squares in 2 ways, for example, as 842309115076 + 378711006025 = 917774^2 + 615395^2 .

It is not a de Polignac number, because 1221020121101 - 2²² = 1221015926797 is a prime.

It is a super-2 number, since 2×1221020121101² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020121109) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3291431 + ... + 3643563.

It is an arithmetic number, because the mean of its divisors is an integer number (111846972573).

Almost surely, 2^{1221020121101} is an apocalyptic number.

1221020121101 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221020121101 is a deficient number, since it is larger than the sum of its proper divisors (121143549775).

1221020121101 is a wasteful number, since it uses less digits than its factorization.

1221020121101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380812 (or 380801 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221020121101 its reverse (1011210201221), we get a palindrome (2232230322322).

The spelling of 1221020121101 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred twenty-one thousand, one hundred one".