20513564517 has 4 divisors (see below), whose sum is σ = 27351419360. Its totient is φ = 13675709676.

The previous prime is 20513564443. The next prime is 20513564537. The reversal of 20513564517 is 71546531502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20513564517 - 2¹¹ = 20513562469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513564537) 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 3 ways as a sum of consecutive naturals, for example, 3418927417 + ... + 3418927422.

It is an arithmetic number, because the mean of its divisors is an integer number (6837854840).

Almost surely, 2^20513564517 is an apocalyptic number.

It is an amenable number.

20513564517 is a deficient number, since it is larger than the sum of its proper divisors (6837854843).

20513564517 is an equidigital number, since it uses as much as digits as its factorization.

20513564517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6837854842.

The product of its (nonzero) digits is 126000, while the sum is 39.

The spelling of 20513564517 in words is "twenty billion, five hundred thirteen million, five hundred sixty-four thousand, five hundred seventeen".