821243442525 has 48 divisors (see below), whose sum is σ = 1483172088768. Its totient is φ = 397655104000.

The previous prime is 821243442517. The next prime is 821243442527. The reversal of 821243442525 is 525244342128.

It is a happy number.

It is not a de Polignac number, because 821243442525 - 2³ = 821243442517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821243442527) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26214 + ... + 1281863.

It is an arithmetic number, because the mean of its divisors is an integer number (30899418516).

Almost surely, 2^821243442525 is an apocalyptic number.

It is an amenable number.

821243442525 is a deficient number, since it is larger than the sum of its proper divisors (661928646243).

821243442525 is a wasteful number, since it uses less digits than its factorization.

821243442525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1308862 (or 1308857 counting only the distinct ones).

The product of its digits is 614400, while the sum is 42.

The spelling of 821243442525 in words is "eight hundred twenty-one billion, two hundred forty-three million, four hundred forty-two thousand, five hundred twenty-five".