18898381 has 4 divisors (see below), whose sum is σ = 18908064. Its totient is φ = 18888700.

The previous prime is 18898361. The next prime is 18898393. The reversal of 18898381 is 18389881.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18389881 = 157 ⋅117133.

It is a cyclic number.

It is not a de Polignac number, because 18898381 - 2²³ = 10509773 is a prime.

It is a super-2 number, since 2×18898381² = 714297608842322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18898351) 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, 775 + ... + 6196.

It is an arithmetic number, because the mean of its divisors is an integer number (4727016).

Almost surely, 2^18898381 is an apocalyptic number.

It is an amenable number.

18898381 is a deficient number, since it is larger than the sum of its proper divisors (9683).

18898381 is an equidigital number, since it uses as much as digits as its factorization.

18898381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9682.

The product of its digits is 110592, while the sum is 46.

The square root of 18898381 is about 4347.2268171790. The cubic root of 18898381 is about 266.3635943978.

The spelling of 18898381 in words is "eighteen million, eight hundred ninety-eight thousand, three hundred eighty-one".