18340381 has 6 divisors (see below), whose sum is σ = 18485790. Its totient is φ = 18195768.

The previous prime is 18340373. The next prime is 18340391. The reversal of 18340381 is 18304381.

It can be written as a sum of positive squares in only one way, i.e., 18020025 + 320356 = 4245^2 + 566^2 .

It is not a de Polignac number, because 18340381 - 2³ = 18340373 is a prime.

It is a super-2 number, since 2×18340381² = 672739150450322, 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 (18340391) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 64666 + ... + 64948.

It is an arithmetic number, because the mean of its divisors is an integer number (3080965).

Almost surely, 2^18340381 is an apocalyptic number.

It is an amenable number.

18340381 is a deficient number, since it is larger than the sum of its proper divisors (145409).

18340381 is an frugal number, since it uses more digits than its factorization.

18340381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795 (or 512 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 18340381 is about 4282.5671039693. The cubic root of 18340381 is about 263.7157801714.

It can be divided in two parts, 18340 and 381, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 18340381 in words is "eighteen million, three hundred forty thousand, three hundred eighty-one".