18103561 has 16 divisors (see below), whose sum is σ = 22067200. Its totient is φ = 14506128.

The previous prime is 18103537. The next prime is 18103571. The reversal of 18103561 is 16530181.

18103561 is nontrivially palindromic in base 6.

It is not a de Polignac number, because 18103561 - 2⁷ = 18103433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18103571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9646 + ... + 11368.

It is an arithmetic number, because the mean of its divisors is an integer number (1379200).

Almost surely, 2^18103561 is an apocalyptic number.

It is an amenable number.

18103561 is a deficient number, since it is larger than the sum of its proper divisors (3963639).

18103561 is a wasteful number, since it uses less digits than its factorization.

18103561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1828.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 18103561 is about 4254.8279636197. The cubic root of 18103561 is about 262.5757834103.

The spelling of 18103561 in words is "eighteen million, one hundred three thousand, five hundred sixty-one".