123211331021 has 2 divisors, whose sum is σ = 123211331022. Its totient is φ = 123211331020.

The previous prime is 123211331003. The next prime is 123211331041. The reversal of 123211331021 is 120133112321.

It is a happy number.

It is an a-pointer prime, because the next prime (123211331041) can be obtained adding 123211331021 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80863453225 + 42347877796 = 284365^2 + 205786^2 .

It is an emirp because it is prime and its reverse (120133112321) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123211331021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 123211330984 and 123211331002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123211331041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61605665510 + 61605665511.

It is an arithmetic number, because the mean of its divisors is an integer number (61605665511).

Almost surely, 2^123211331021 is an apocalyptic number.

It is an amenable number.

123211331021 is a deficient number, since it is larger than the sum of its proper divisors (1).

123211331021 is an equidigital number, since it uses as much as digits as its factorization.

123211331021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 123211331021 its reverse (120133112321), we get a palindrome (243344443342).

The spelling of 123211331021 in words is "one hundred twenty-three billion, two hundred eleven million, three hundred thirty-one thousand, twenty-one".