11565520573 has 4 divisors (see below), whose sum is σ = 11567035548. Its totient is φ = 11564005600.

The previous prime is 11565520567. The next prime is 11565520591. The reversal of 11565520573 is 37502556511.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9987603844 + 1577916729 = 99938^2 + 39723^2 .

It is a cyclic number.

It is not a de Polignac number, because 11565520573 - 2¹⁷ = 11565389501 is a prime.

It is a super-2 number, since 2×11565520573² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11565520523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 745978 + ... + 761323.

It is an arithmetic number, because the mean of its divisors is an integer number (2891758887).

Almost surely, 2^11565520573 is an apocalyptic number.

It is an amenable number.

11565520573 is a deficient number, since it is larger than the sum of its proper divisors (1514975).

11565520573 is an equidigital number, since it uses as much as digits as its factorization.

11565520573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1514974.

The product of its (nonzero) digits is 157500, while the sum is 40.

The spelling of 11565520573 in words is "eleven billion, five hundred sixty-five million, five hundred twenty thousand, five hundred seventy-three".