131212321 has 2 divisors, whose sum is σ = 131212322. Its totient is φ = 131212320.

The previous prime is 131212313. The next prime is 131212343. The reversal of 131212321 is 123212131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111007296 + 20205025 = 10536^2 + 4495^2 .

It is a cyclic number.

It is not a de Polignac number, because 131212321 - 2³ = 131212313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131212295 and 131212304.

It is not a weakly prime, because it can be changed into another prime (131212021) 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 as a sum of consecutive naturals, namely, 65606160 + 65606161.

It is an arithmetic number, because the mean of its divisors is an integer number (65606161).

Almost surely, 2^131212321 is an apocalyptic number.

It is an amenable number.

131212321 is a deficient number, since it is larger than the sum of its proper divisors (1).

131212321 is an equidigital number, since it uses as much as digits as its factorization.

131212321 is an odious number, because the sum of its binary digits is odd.

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

The square root of 131212321 is about 11454.7946729743. The cubic root of 131212321 is about 508.1495428980.

Adding to 131212321 its reverse (123212131), we get a palindrome (254424452).

The spelling of 131212321 in words is "one hundred thirty-one million, two hundred twelve thousand, three hundred twenty-one".