21243076957493 has 2 divisors, whose sum is σ = 21243076957494. Its totient is φ = 21243076957492.

The previous prime is 21243076957481. The next prime is 21243076957507. The reversal of 21243076957493 is 39475967034212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18126323280004 + 3116753677489 = 4257502^2 + 1765433^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243076957493 - 2¹⁰ = 21243076956469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243076957433) 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, 10621538478746 + 10621538478747.

It is an arithmetic number, because the mean of its divisors is an integer number (10621538478747).

Almost surely, 2^{21243076957493} is an apocalyptic number.

It is an amenable number.

21243076957493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243076957493 is an equidigital number, since it uses as much as digits as its factorization.

21243076957493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68584320, while the sum is 62.

The spelling of 21243076957493 in words is "twenty-one trillion, two hundred forty-three billion, seventy-six million, nine hundred fifty-seven thousand, four hundred ninety-three".