121211112221021 has 4 divisors (see below), whose sum is σ = 127590644443200. Its totient is φ = 114831579998844.

The previous prime is 121211112221009. The next prime is 121211112221081. The reversal of 121211112221021 is 120122211112121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121211112221021 - 2¹⁸ = 121211111958877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121211112220984 and 121211112221002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211112221081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3189766111061 + ... + 3189766111098.

It is an arithmetic number, because the mean of its divisors is an integer number (31897661110800).

Almost surely, 2^{121211112221021} is an apocalyptic number.

It is an amenable number.

121211112221021 is a deficient number, since it is larger than the sum of its proper divisors (6379532222179).

121211112221021 is an equidigital number, since it uses as much as digits as its factorization.

121211112221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6379532222178.

The product of its (nonzero) digits is 64, while the sum is 20.

Adding to 121211112221021 its reverse (120122211112121), we get a palindrome (241333323333142).

The spelling of 121211112221021 in words is "one hundred twenty-one trillion, two hundred eleven billion, one hundred twelve million, two hundred twenty-one thousand, twenty-one".