821534425493 has 2 divisors, whose sum is σ = 821534425494. Its totient is φ = 821534425492.

The previous prime is 821534425441. The next prime is 821534425519. The reversal of 821534425493 is 394524435128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 809499677284 + 12034748209 = 899722^2 + 109703^2 .

It is a cyclic number.

It is not a de Polignac number, because 821534425493 - 2¹⁸ = 821534163349 is a prime.

It is a super-2 number, since 2×821534425493² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821534425993) 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, 410767212746 + 410767212747.

It is an arithmetic number, because the mean of its divisors is an integer number (410767212747).

Almost surely, 2^821534425493 is an apocalyptic number.

It is an amenable number.

821534425493 is a deficient number, since it is larger than the sum of its proper divisors (1).

821534425493 is an equidigital number, since it uses as much as digits as its factorization.

821534425493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4147200, while the sum is 50.

The spelling of 821534425493 in words is "eight hundred twenty-one billion, five hundred thirty-four million, four hundred twenty-five thousand, four hundred ninety-three".