12816117731821 has 2 divisors, whose sum is σ = 12816117731822. Its totient is φ = 12816117731820.

The previous prime is 12816117731789. The next prime is 12816117731861. The reversal of 12816117731821 is 12813771161821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12673165683721 + 142952048100 = 3559939^2 + 378090^2 .

It is a cyclic number.

It is not a de Polignac number, because 12816117731821 - 2⁵ = 12816117731789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12816117731861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6408058865910 + 6408058865911.

It is an arithmetic number, because the mean of its divisors is an integer number (6408058865911).

Almost surely, 2^{12816117731821} is an apocalyptic number.

It is an amenable number.

12816117731821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12816117731821 is an equidigital number, since it uses as much as digits as its factorization.

12816117731821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 49.

The spelling of 12816117731821 in words is "twelve trillion, eight hundred sixteen billion, one hundred seventeen million, seven hundred thirty-one thousand, eight hundred twenty-one".