18067561 has 4 divisors (see below), whose sum is σ = 18076500. Its totient is φ = 18058624.

The previous prime is 18067559. The next prime is 18067571. The reversal of 18067561 is 16576081.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16576081 = 29 ⋅571589.

It can be written as a sum of positive squares in 2 ways, for example, as 11971600 + 6095961 = 3460^2 + 2469^2 .

It is a cyclic number.

It is not a de Polignac number, because 18067561 - 2¹ = 18067559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18067571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165 + ... + 6013.

It is an arithmetic number, because the mean of its divisors is an integer number (4519125).

Almost surely, 2^18067561 is an apocalyptic number.

It is an amenable number.

18067561 is a deficient number, since it is larger than the sum of its proper divisors (8939).

18067561 is an equidigital number, since it uses as much as digits as its factorization.

18067561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8938.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 18067561 is about 4250.5953700629. The cubic root of 18067561 is about 262.4016187639.

The spelling of 18067561 in words is "eighteen million, sixty-seven thousand, five hundred sixty-one".