121211220121021 has 4 divisors (see below), whose sum is σ = 121347873132192. Its totient is φ = 121074567109852.

The previous prime is 121211220121009. The next prime is 121211220121027. The reversal of 121211220121021 is 120121022112121.

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 121211220121021 - 2⁵ = 121211220120989 is a prime.

It is a super-2 number, since 2×121211220121021² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121211220121021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211220121027) 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, 68326504255 + ... + 68326506028.

It is an arithmetic number, because the mean of its divisors is an integer number (30336968283048).

Almost surely, 2^{121211220121021} is an apocalyptic number.

It is an amenable number.

121211220121021 is a deficient number, since it is larger than the sum of its proper divisors (136653011171).

121211220121021 is an equidigital number, since it uses as much as digits as its factorization.

121211220121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136653011170.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 121211220121021 its reverse (120121022112121), we get a palindrome (241332242233142).

The spelling of 121211220121021 in words is "one hundred twenty-one trillion, two hundred eleven billion, two hundred twenty million, one hundred twenty-one thousand, twenty-one".