18207381 has 4 divisors (see below), whose sum is σ = 24276512. Its totient is φ = 12138252.

The previous prime is 18207379. The next prime is 18207407. The reversal of 18207381 is 18370281.

It is a happy number.

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 an emirpimes, since its reverse is a distinct semiprime: 18370281 = 3 ⋅6123427.

It is not a de Polignac number, because 18207381 - 2¹ = 18207379 is a prime.

It is a super-2 number, since 2×18207381² = 663017445758322, 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 (18207781) 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, 3034561 + ... + 3034566.

It is an arithmetic number, because the mean of its divisors is an integer number (6069128).

Almost surely, 2^18207381 is an apocalyptic number.

It is an amenable number.

18207381 is a deficient number, since it is larger than the sum of its proper divisors (6069131).

18207381 is an equidigital number, since it uses as much as digits as its factorization.

18207381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6069130.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 18207381 is about 4267.0107803942. The cubic root of 18207381 is about 263.0767653623.

The spelling of 18207381 in words is "eighteen million, two hundred seven thousand, three hundred eighty-one".