12891998321 has 2 divisors, whose sum is σ = 12891998322. Its totient is φ = 12891998320.

The previous prime is 12891998291. The next prime is 12891998333. The reversal of 12891998321 is 12389919821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12890423296 + 1575025 = 113536^2 + 1255^2 .

It is a cyclic number.

It is not a de Polignac number, because 12891998321 - 2¹⁰ = 12891997297 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (12891998521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6445999160 + 6445999161.

It is an arithmetic number, because the mean of its divisors is an integer number (6445999161).

Almost surely, 2^12891998321 is an apocalyptic number.

It is an amenable number.

12891998321 is a deficient number, since it is larger than the sum of its proper divisors (1).

12891998321 is an equidigital number, since it uses as much as digits as its factorization.

12891998321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 53.

The spelling of 12891998321 in words is "twelve billion, eight hundred ninety-one million, nine hundred ninety-eight thousand, three hundred twenty-one".