18041561 has 8 divisors (see below), whose sum is σ = 18506880. Its totient is φ = 17579728.

The previous prime is 18041557. The next prime is 18041563. The reversal of 18041561 is 16514081.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18041561 - 2² = 18041557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18041561.

It is not an unprimeable number, because it can be changed into a prime (18041563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11930 + ... + 13356.

It is an arithmetic number, because the mean of its divisors is an integer number (2313360).

Almost surely, 2^18041561 is an apocalyptic number.

It is an amenable number.

18041561 is a deficient number, since it is larger than the sum of its proper divisors (465319).

18041561 is a wasteful number, since it uses less digits than its factorization.

18041561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1743.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 18041561 is about 4247.5358738921. The cubic root of 18041561 is about 262.2756892540.

The spelling of 18041561 in words is "eighteen million, forty-one thousand, five hundred sixty-one".