11536506505561 has 4 divisors (see below), whose sum is σ = 11537368674724. Its totient is φ = 11535644336400.

The previous prime is 11536506505547. The next prime is 11536506505639. The reversal of 11536506505561 is 16550560563511.

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 4731686459536 + 6804820046025 = 2175244^2 + 2608605^2 .

It is a cyclic number.

It is not a de Polignac number, because 11536506505561 - 2⁹ = 11536506505049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11536506506561) 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, 431064510 + ... + 431091271.

It is an arithmetic number, because the mean of its divisors is an integer number (2884342168681).

Almost surely, 2^{11536506505561} is an apocalyptic number.

It is an amenable number.

11536506505561 is a deficient number, since it is larger than the sum of its proper divisors (862169163).

11536506505561 is an equidigital number, since it uses as much as digits as its factorization.

11536506505561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 862169162.

The product of its (nonzero) digits is 2025000, while the sum is 49.

The spelling of 11536506505561 in words is "eleven trillion, five hundred thirty-six billion, five hundred six million, five hundred five thousand, five hundred sixty-one".