1331212021 has 2 divisors, whose sum is σ = 1331212022. Its totient is φ = 1331212020.

The previous prime is 1331212007. The next prime is 1331212031. The reversal of 1331212021 is 1202121331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1122987121 + 208224900 = 33511^2 + 14430^2 .

It is an emirp because it is prime and its reverse (1202121331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1331212021 - 2²⁵ = 1297657589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1331211986 and 1331212004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331212031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665606010 + 665606011.

It is an arithmetic number, because the mean of its divisors is an integer number (665606011).

Almost surely, 2^1331212021 is an apocalyptic number.

It is an amenable number.

1331212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331212021 is an equidigital number, since it uses as much as digits as its factorization.

1331212021 is an odious number, because the sum of its binary digits is odd.

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

The square root of 1331212021 is about 36485.7783389638. The cubic root of 1331212021 is about 1100.0584048879.

Adding to 1331212021 its reverse (1202121331), we get a palindrome (2533333352).

The spelling of 1331212021 in words is "one billion, three hundred thirty-one million, two hundred twelve thousand, twenty-one".