12397756421 has 2 divisors, whose sum is σ = 12397756422. Its totient is φ = 12397756420.

The previous prime is 12397756403. The next prime is 12397756433. The reversal of 12397756421 is 12465779321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11001912100 + 1395844321 = 104890^2 + 37361^2 .

It is an emirp because it is prime and its reverse (12465779321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12397756421 - 2¹⁰ = 12397755397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12397756451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6198878210 + 6198878211.

It is an arithmetic number, because the mean of its divisors is an integer number (6198878211).

Almost surely, 2^12397756421 is an apocalyptic number.

It is an amenable number.

12397756421 is a deficient number, since it is larger than the sum of its proper divisors (1).

12397756421 is an equidigital number, since it uses as much as digits as its factorization.

12397756421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 47.

The spelling of 12397756421 in words is "twelve billion, three hundred ninety-seven million, seven hundred fifty-six thousand, four hundred twenty-one".