21312131242081 has 2 divisors, whose sum is σ = 21312131242082. Its totient is φ = 21312131242080.

The previous prime is 21312131241991. The next prime is 21312131242109. The reversal of 21312131242081 is 18024213121312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20443057960000 + 869073282081 = 4521400^2 + 932241^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312131242081 - 2⁴¹ = 19113107986529 is a prime.

It is a super-2 number, since 2×21312131242081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21312131242781) 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, 10656065621040 + 10656065621041.

It is an arithmetic number, because the mean of its divisors is an integer number (10656065621041).

Almost surely, 2^{21312131242081} is an apocalyptic number.

It is an amenable number.

21312131242081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312131242081 is an equidigital number, since it uses as much as digits as its factorization.

21312131242081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 31.

Adding to 21312131242081 its reverse (18024213121312), we get a palindrome (39336344363393).

The spelling of 21312131242081 in words is "twenty-one trillion, three hundred twelve billion, one hundred thirty-one million, two hundred forty-two thousand, eighty-one".