12212121 has 8 divisors (see below), whose sum is σ = 16308864. Its totient is φ = 8128400.

The previous prime is 12212119. The next prime is 12212131. The reversal of 12212121 is 12121221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12212121 - 2¹ = 12212119 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12212097 and 12212106.

It is not an unprimeable number, because it can be changed into a prime (12212111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 801 + ... + 5006.

It is an arithmetic number, because the mean of its divisors is an integer number (2038608).

Almost surely, 2^12212121 is an apocalyptic number.

It is an amenable number.

12212121 is a deficient number, since it is larger than the sum of its proper divisors (4096743).

12212121 is an equidigital number, since it uses as much as digits as its factorization.

12212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6511.

The product of its digits is 16, while the sum is 12.

The square root of 12212121 is about 3494.5845246610. The cubic root of 12212121 is about 230.2839655825.

Adding to 12212121 its reverse (12121221), we get a palindrome (24333342).

It can be divided in two parts, 12 and 212121, that multiplied together give a palindrome (2545452).

The spelling of 12212121 in words is "twelve million, two hundred twelve thousand, one hundred twenty-one".