16535320561 has 2 divisors, whose sum is σ = 16535320562. Its totient is φ = 16535320560.

The previous prime is 16535320531. The next prime is 16535320567. The reversal of 16535320561 is 16502353561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10076144400 + 6459176161 = 100380^2 + 80369^2 .

It is a cyclic number.

It is not a de Polignac number, because 16535320561 - 2²⁷ = 16401102833 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16535320561.

It is not a weakly prime, because it can be changed into another prime (16535320567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8267660280 + 8267660281.

It is an arithmetic number, because the mean of its divisors is an integer number (8267660281).

Almost surely, 2^16535320561 is an apocalyptic number.

It is an amenable number.

16535320561 is a deficient number, since it is larger than the sum of its proper divisors (1).

16535320561 is an equidigital number, since it uses as much as digits as its factorization.

16535320561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81000, while the sum is 37.

The spelling of 16535320561 in words is "sixteen billion, five hundred thirty-five million, three hundred twenty thousand, five hundred sixty-one".