123212121 has 8 divisors (see below), whose sum is σ = 167382720. Its totient is φ = 80591472.

The previous prime is 123212087. The next prime is 123212143. The reversal of 123212121 is 121212321.

123212121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

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

It is not a de Polignac number, because 123212121 - 2⁷ = 123211993 is a prime.

It is a super-2 number, since 2×123212121² = 30362453522637282, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 123212121.

It is not an unprimeable number, because it can be changed into a prime (123212161) 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, 387301 + ... + 387618.

It is an arithmetic number, because the mean of its divisors is an integer number (20922840).

Almost surely, 2^123212121 is an apocalyptic number.

It is an amenable number.

123212121 is a deficient number, since it is larger than the sum of its proper divisors (44170599).

123212121 is an equidigital number, since it uses as much as digits as its factorization.

123212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 774975.

The product of its digits is 48, while the sum is 15.

The square root of 123212121 is about 11100.0955401294. The cubic root of 123212121 is about 497.6047047788.

Adding to 123212121 its reverse (121212321), we get a palindrome (244424442).

The spelling of 123212121 in words is "one hundred twenty-three million, two hundred twelve thousand, one hundred twenty-one".