121211111202021 has 18 divisors (see below), whose sum is σ = 179942572455282. Its totient is φ = 78623423474400.

The previous prime is 121211111202011. The next prime is 121211111202047. The reversal of 121211111202021 is 120202111112121.

It is a happy number.

121211111202021 is a `hidden beast` number, since 121 + 211 + 11 + 120 + 202 + 1 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 38023687332225 + 83187423869796 = 6166335^2 + 9120714^2 .

It is not a de Polignac number, because 121211111202021 - 2²³ = 121211102813413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121211111201985 and 121211111202003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211111202011) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4918870530 + ... + 4918895171.

It is an arithmetic number, because the mean of its divisors is an integer number (9996809580849).

Almost surely, 2^{121211111202021} is an apocalyptic number.

It is an amenable number.

121211111202021 is a deficient number, since it is larger than the sum of its proper divisors (58731461253261).

121211111202021 is an equidigital number, since it uses as much as digits as its factorization.

121211111202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9837765781 (or 9837765741 counting only the distinct ones).

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

Adding to 121211111202021 its reverse (120202111112121), we get a palindrome (241413222314142).

The spelling of 121211111202021 in words is "one hundred twenty-one trillion, two hundred eleven billion, one hundred eleven million, two hundred two thousand, twenty-one".