131212021 has 2 divisors, whose sum is σ = 131212022. Its totient is φ = 131212020.

The previous prime is 131212019. The next prime is 131212031. The reversal of 131212021 is 120212131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121220100 + 9991921 = 11010^2 + 3161^2 .

It is a cyclic number.

It is not a de Polignac number, because 131212021 - 2¹ = 131212019 is a prime.

Together with 131212019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 131211992 and 131212010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131212031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65606010 + 65606011.

It is an arithmetic number, because the mean of its divisors is an integer number (65606011).

Almost surely, 2^131212021 is an apocalyptic number.

It is an amenable number.

131212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

131212021 is an equidigital number, since it uses as much as digits as its factorization.

131212021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 131212021 is about 11454.7815780136. The cubic root of 131212021 is about 508.1491556250.

Adding to 131212021 its reverse (120212131), we get a palindrome (251424152).

The spelling of 131212021 in words is "one hundred thirty-one million, two hundred twelve thousand, twenty-one".