123213121 has 4 divisors (see below), whose sum is σ = 123455700. Its totient is φ = 122970544.

The previous prime is 123213091. The next prime is 123213137. The reversal of 123213121 is 121312321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 107412496 + 15800625 = 10364^2 + 3975^2 .

It is a cyclic number.

It is not a de Polignac number, because 123213121 - 2⁵ = 123213089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123213095 and 123213104.

It is not an unprimeable number, because it can be changed into a prime (123213151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120526 + ... + 121543.

It is an arithmetic number, because the mean of its divisors is an integer number (30863925).

Almost surely, 2^123213121 is an apocalyptic number.

It is an amenable number.

123213121 is a deficient number, since it is larger than the sum of its proper divisors (242579).

123213121 is an equidigital number, since it uses as much as digits as its factorization.

123213121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242578.

The product of its digits is 72, while the sum is 16.

The square root of 123213121 is about 11100.1405846953. The cubic root of 123213121 is about 497.6060509757.

Adding to 123213121 its reverse (121312321), we get a palindrome (244525442).

The spelling of 123213121 in words is "one hundred twenty-three million, two hundred thirteen thousand, one hundred twenty-one".