11111221202121 has 24 divisors (see below), whose sum is σ = 17015032929024. Its totient is φ = 6974785752480.

The previous prime is 11111221202089. The next prime is 11111221202153. The reversal of 11111221202121 is 12120212211111.

It is a happy number.

11111221202121 is a `hidden beast` number, since 11 + 111 + 221 + 202 + 121 = 666.

It is an interprime number because it is at equal distance from previous prime (11111221202089) and next prime (11111221202153).

It is not a de Polignac number, because 11111221202121 - 2⁵ = 11111221202089 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11111221202094 and 11111221202103.

It is not an unprimeable number, because it can be changed into a prime (11111221204121) 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 23 ways as a sum of consecutive naturals, for example, 538167591 + ... + 538188236.

It is an arithmetic number, because the mean of its divisors is an integer number (708959705376).

Almost surely, 2^{11111221202121} is an apocalyptic number.

It is an amenable number.

11111221202121 is a deficient number, since it is larger than the sum of its proper divisors (5903811726903).

11111221202121 is a wasteful number, since it uses less digits than its factorization.

11111221202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076355901 (or 1076355898 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 11111221202121 its reverse (12120212211111), we get a palindrome (23231433413232).

The spelling of 11111221202121 in words is "eleven trillion, one hundred eleven billion, two hundred twenty-one million, two hundred two thousand, one hundred twenty-one".