21243937019 has 2 divisors, whose sum is σ = 21243937020. Its totient is φ = 21243937018.

The previous prime is 21243937003. The next prime is 21243937061. The reversal of 21243937019 is 91073934212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21243937019 - 2⁴ = 21243937003 is a prime.

It is a super-3 number, since 3×21243937019³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21243937079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621968509 + 10621968510.

It is an arithmetic number, because the mean of its divisors is an integer number (10621968510).

Almost surely, 2^21243937019 is an apocalyptic number.

21243937019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243937019 is an equidigital number, since it uses as much as digits as its factorization.

21243937019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 41.

The spelling of 21243937019 in words is "twenty-one billion, two hundred forty-three million, nine hundred thirty-seven thousand, nineteen".