18181398 has 16 divisors (see below), whose sum is σ = 38502000. Its totient is φ = 5703936.

The previous prime is 18181391. The next prime is 18181411. The reversal of 18181398 is 89318181.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18181391) 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, 89023 + ... + 89226.

It is an arithmetic number, because the mean of its divisors is an integer number (2406375).

Almost surely, 2^18181398 is an apocalyptic number.

18181398 is an abundant number, since it is smaller than the sum of its proper divisors (20320602).

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

18181398 is a wasteful number, since it uses less digits than its factorization.

18181398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178271.

The product of its digits is 13824, while the sum is 39.

The square root of 18181398 is about 4263.9650561420. The cubic root of 18181398 is about 262.9515637982.

The spelling of 18181398 in words is "eighteen million, one hundred eighty-one thousand, three hundred ninety-eight".