121212121221 has 20 divisors (see below), whose sum is σ = 188942568672. Its totient is φ = 77294684808.

The previous prime is 121212121201. The next prime is 121212121223. The reversal of 121212121221 is 122121212121.

It is not a de Polignac number, because 121212121221 - 2²³ = 121203732613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121212121194 and 121212121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121212121223) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 32529571 + ... + 32533296.

Almost surely, 2^121212121221 is an apocalyptic number.

It is an amenable number.

121212121221 is a deficient number, since it is larger than the sum of its proper divisors (67730447451).

121212121221 is an equidigital number, since it uses as much as digits as its factorization.

121212121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65062902 (or 65062893 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 121212121221 its reverse (122121212121), we get a palindrome (243333333342).

It can be divided in two parts, 1212121212 and 21, that multiplied together give a palindrome (25454545452).

The spelling of 121212121221 in words is "one hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".