18561798 has 56 divisors (see below), whose sum is σ = 43282800. Its totient is φ = 5960304.

The previous prime is 18561797. The next prime is 18561811. The reversal of 18561798 is 89716581.

18561798 is a `hidden beast` number, since 18 + 561 + 79 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18561791) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 42063 + ... + 42501.

Almost surely, 2^18561798 is an apocalyptic number.

18561798 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18561798, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21641400).

18561798 is an abundant number, since it is smaller than the sum of its proper divisors (24721002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18561798 is an equidigital number, since it uses as much as digits as its factorization.

18561798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488 (or 473 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 18561798 is about 4308.3405157903. The cubic root of 18561798 is about 264.7727873235.

The spelling of 18561798 in words is "eighteen million, five hundred sixty-one thousand, seven hundred ninety-eight".