18561493 has 8 divisors (see below), whose sum is σ = 18825048. Its totient is φ = 18299904.

The previous prime is 18561443. The next prime is 18561503. The reversal of 18561493 is 39416581.

It can be written as a sum of positive squares in 4 ways, for example, as 54289 + 18507204 = 233^2 + 4302^2 .

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 18561493 - 2⁹ = 18560981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18561443) 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, 31005 + ... + 31597.

It is an arithmetic number, because the mean of its divisors is an integer number (2353131).

Almost surely, 2^18561493 is an apocalyptic number.

It is an amenable number.

18561493 is a deficient number, since it is larger than the sum of its proper divisors (263555).

18561493 is a wasteful number, since it uses less digits than its factorization.

18561493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 983.

The product of its digits is 25920, while the sum is 37.

The square root of 18561493 is about 4308.3051191855. The cubic root of 18561493 is about 264.7713371022.

The spelling of 18561493 in words is "eighteen million, five hundred sixty-one thousand, four hundred ninety-three".