21531204523413 has 96 divisors (see below), whose sum is σ = 34557044121600. Its totient is φ = 12834362120832.

The previous prime is 21531204523267. The next prime is 21531204523417. The reversal of 21531204523413 is 31432540213512.

21531204523413 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 120 + 4 + 523 + 4 + 1 + 3 = 666.

It is not a de Polignac number, because 21531204523413 - 2¹³ = 21531204515221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531204523417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 642648220 + ... + 642681722.

It is an arithmetic number, because the mean of its divisors is an integer number (359969209600).

Almost surely, 2^{21531204523413} is an apocalyptic number.

It is an amenable number.

21531204523413 is a deficient number, since it is larger than the sum of its proper divisors (13025839598187).

21531204523413 is a wasteful number, since it uses less digits than its factorization.

21531204523413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34623 (or 34620 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

Adding to 21531204523413 its reverse (31432540213512), we get a palindrome (52963744736925).

The spelling of 21531204523413 in words is "twenty-one trillion, five hundred thirty-one billion, two hundred four million, five hundred twenty-three thousand, four hundred thirteen".