21585841523 has 2 divisors, whose sum is σ = 21585841524. Its totient is φ = 21585841522.

The previous prime is 21585841517. The next prime is 21585841567. The reversal of 21585841523 is 32514858512.

It is an a-pointer prime, because the next prime (21585841567) can be obtained adding 21585841523 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21585841523 - 2⁸ = 21585841267 is a prime.

It is not a weakly prime, because it can be changed into another prime (21585841583) 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, 10792920761 + 10792920762.

It is an arithmetic number, because the mean of its divisors is an integer number (10792920762).

Almost surely, 2^21585841523 is an apocalyptic number.

21585841523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21585841523 is an equidigital number, since it uses as much as digits as its factorization.

21585841523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384000, while the sum is 44.

The spelling of 21585841523 in words is "twenty-one billion, five hundred eighty-five million, eight hundred forty-one thousand, five hundred twenty-three".