21524552521 has 8 divisors (see below), whose sum is σ = 22294326600. Its totient is φ = 20756615040.

The previous prime is 21524552513. The next prime is 21524552561. The reversal of 21524552521 is 12525542512.

It can be written as a sum of positive squares in 4 ways, for example, as 9525760000 + 11998792521 = 97600^2 + 109539^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21524552521 - 2³ = 21524552513 is a prime.

It is a super-2 number, since 2×21524552521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21524552501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 435270 + ... + 482191.

It is an arithmetic number, because the mean of its divisors is an integer number (2786790825).

Almost surely, 2^21524552521 is an apocalyptic number.

It is an amenable number.

21524552521 is a deficient number, since it is larger than the sum of its proper divisors (769774079).

21524552521 is an equidigital number, since it uses as much as digits as its factorization.

21524552521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918299.

The product of its digits is 40000, while the sum is 34.

The spelling of 21524552521 in words is "twenty-one billion, five hundred twenty-four million, five hundred fifty-two thousand, five hundred twenty-one".