20530521521 has 8 divisors (see below), whose sum is σ = 20673197160. Its totient is φ = 20387996928.

The previous prime is 20530521509. The next prime is 20530521553. The reversal of 20530521521 is 12512503502.

It can be written as a sum of positive squares in 4 ways, for example, as 4155736225 + 16374785296 = 64465^2 + 127964^2 .

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 20530521521 - 2¹⁰ = 20530520497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20530571521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242195 + ... + 315783.

It is an arithmetic number, because the mean of its divisors is an integer number (2584149645).

Almost surely, 2^20530521521 is an apocalyptic number.

It is an amenable number.

20530521521 is a deficient number, since it is larger than the sum of its proper divisors (142675639).

20530521521 is a wasteful number, since it uses less digits than its factorization.

20530521521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75523.

The product of its (nonzero) digits is 3000, while the sum is 26.

The spelling of 20530521521 in words is "twenty billion, five hundred thirty million, five hundred twenty-one thousand, five hundred twenty-one".