20116520561 has 4 divisors (see below), whose sum is σ = 20116955712. Its totient is φ = 20116085412.

The previous prime is 20116520551. The next prime is 20116520573. The reversal of 20116520561 is 16502561102.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 20116520561 - 2⁶ = 20116520497 is a prime.

It is a super-2 number, since 2×20116520561² (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 (20116520551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138701 + ... + 243866.

It is an arithmetic number, because the mean of its divisors is an integer number (5029238928).

Almost surely, 2^20116520561 is an apocalyptic number.

It is an amenable number.

20116520561 is a deficient number, since it is larger than the sum of its proper divisors (435151).

20116520561 is an equidigital number, since it uses as much as digits as its factorization.

20116520561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435150.

The product of its (nonzero) digits is 3600, while the sum is 29.

The spelling of 20116520561 in words is "twenty billion, one hundred sixteen million, five hundred twenty thousand, five hundred sixty-one".