21011212331 has 2 divisors, whose sum is σ = 21011212332. Its totient is φ = 21011212330.

The previous prime is 21011212297. The next prime is 21011212349. The reversal of 21011212331 is 13321211012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21011212331 - 2⁶ = 21011212267 is a prime.

It is a super-2 number, since 2×21011212331² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21011212031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505606165 + 10505606166.

It is an arithmetic number, because the mean of its divisors is an integer number (10505606166).

Almost surely, 2^21011212331 is an apocalyptic number.

21011212331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011212331 is an equidigital number, since it uses as much as digits as its factorization.

21011212331 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 17.

Adding to 21011212331 its reverse (13321211012), we get a palindrome (34332423343).

The spelling of 21011212331 in words is "twenty-one billion, eleven million, two hundred twelve thousand, three hundred thirty-one".