18105801561 has 16 divisors (see below), whose sum is σ = 26825814400. Its totient is φ = 12069452304.

The previous prime is 18105801547. The next prime is 18105801569. The reversal of 18105801561 is 16510850181.

18105801561 is a `hidden beast` number, since 1 + 8 + 1 + 0 + 580 + 15 + 61 = 666.

It is not a de Polignac number, because 18105801561 - 2¹¹ = 18105799513 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18105801569) 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 15 ways as a sum of consecutive naturals, for example, 376860 + ... + 422178.

It is an arithmetic number, because the mean of its divisors is an integer number (1676613400).

Almost surely, 2^18105801561 is an apocalyptic number.

It is an amenable number.

18105801561 is a deficient number, since it is larger than the sum of its proper divisors (8720012839).

18105801561 is a wasteful number, since it uses less digits than its factorization.

18105801561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60125 (or 60119 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 36.

The spelling of 18105801561 in words is "eighteen billion, one hundred five million, eight hundred one thousand, five hundred sixty-one".