18595561 has 4 divisors (see below), whose sum is σ = 18910800. Its totient is φ = 18280324.

The previous prime is 18595553. The next prime is 18595609. The reversal of 18595561 is 16559581.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18595561 - 2³ = 18595553 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18595531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157531 + ... + 157648.

It is an arithmetic number, because the mean of its divisors is an integer number (4727700).

Almost surely, 2^18595561 is an apocalyptic number.

18595561 is the 1929-th centered decagonal number.

It is an amenable number.

18595561 is a deficient number, since it is larger than the sum of its proper divisors (315239).

18595561 is an equidigital number, since it uses as much as digits as its factorization.

18595561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315238.

The product of its digits is 54000, while the sum is 40.

The square root of 18595561 is about 4312.2570656212. The cubic root of 18595561 is about 264.9332263231.

The spelling of 18595561 in words is "eighteen million, five hundred ninety-five thousand, five hundred sixty-one".