18326381 has 4 divisors (see below), whose sum is σ = 18716352. Its totient is φ = 17936412.

The previous prime is 18326351. The next prime is 18326387. The reversal of 18326381 is 18362381.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18326381 is a prime.

It is a super-2 number, since 2×18326381² = 671712481114322, 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 (18326387) 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, 194915 + ... + 195008.

It is an arithmetic number, because the mean of its divisors is an integer number (4679088).

Almost surely, 2^18326381 is an apocalyptic number.

It is an amenable number.

18326381 is a deficient number, since it is larger than the sum of its proper divisors (389971).

18326381 is an equidigital number, since it uses as much as digits as its factorization.

18326381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389970.

The product of its digits is 6912, while the sum is 32.

The square root of 18326381 is about 4280.9322582821. The cubic root of 18326381 is about 263.6486612323.

The spelling of 18326381 in words is "eighteen million, three hundred twenty-six thousand, three hundred eighty-one".