21821231599493 has 2 divisors, whose sum is σ = 21821231599494. Its totient is φ = 21821231599492.

The previous prime is 21821231599423. The next prime is 21821231599507. The reversal of 21821231599493 is 39499513212812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14049887829124 + 7771343770369 = 3748318^2 + 2787713^2 .

It is a cyclic number.

It is not a de Polignac number, because 21821231599493 - 2¹⁰ = 21821231598469 is a prime.

It is a super-2 number, since 2×21821231599493² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21821231599423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910615799746 + 10910615799747.

It is an arithmetic number, because the mean of its divisors is an integer number (10910615799747).

Almost surely, 2^{21821231599493} is an apocalyptic number.

It is an amenable number.

21821231599493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21821231599493 is an equidigital number, since it uses as much as digits as its factorization.

21821231599493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8398080, while the sum is 59.

The spelling of 21821231599493 in words is "twenty-one trillion, eight hundred twenty-one billion, two hundred thirty-one million, five hundred ninety-nine thousand, four hundred ninety-three".