18716381 has 4 divisors (see below), whose sum is σ = 18980064. Its totient is φ = 18452700.

The previous prime is 18716359. The next prime is 18716407. The reversal of 18716381 is 18361781.

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 not a de Polignac number, because 18716381 - 2¹⁰ = 18715357 is a prime.

It is a super-2 number, since 2×18716381² = 700605835474322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18766381) 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, 131735 + ... + 131876.

It is an arithmetic number, because the mean of its divisors is an integer number (4745016).

Almost surely, 2^18716381 is an apocalyptic number.

It is an amenable number.

18716381 is a deficient number, since it is larger than the sum of its proper divisors (263683).

18716381 is an equidigital number, since it uses as much as digits as its factorization.

18716381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263682.

The product of its digits is 8064, while the sum is 35.

The square root of 18716381 is about 4326.2432895065. The cubic root of 18716381 is about 265.5057672208.

The spelling of 18716381 in words is "eighteen million, seven hundred sixteen thousand, three hundred eighty-one".