18981317 has 4 divisors (see below), whose sum is σ = 18998496. Its totient is φ = 18964140.

The previous prime is 18981307. The next prime is 18981329. The reversal of 18981317 is 71318981.

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 18981317 - 2¹⁰ = 18980293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18981307) 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, 6809 + ... + 9182.

It is an arithmetic number, because the mean of its divisors is an integer number (4749624).

Almost surely, 2^18981317 is an apocalyptic number.

It is an amenable number.

18981317 is a deficient number, since it is larger than the sum of its proper divisors (17179).

18981317 is a wasteful number, since it uses less digits than its factorization.

18981317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17178.

The product of its digits is 12096, while the sum is 38.

The square root of 18981317 is about 4356.7553293707. The cubic root of 18981317 is about 266.7526734729.

The spelling of 18981317 in words is "eighteen million, nine hundred eighty-one thousand, three hundred seventeen".