18863281 has 4 divisors (see below), whose sum is σ = 18875200. Its totient is φ = 18851364.

The previous prime is 18863279. The next prime is 18863287. The reversal of 18863281 is 18236881.

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 18863281 - 2¹ = 18863279 is a prime.

It is a super-2 number, since 2×18863281² = 711646740169922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18863281.

It is not an unprimeable number, because it can be changed into a prime (18863287) 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, 3141 + ... + 6898.

It is an arithmetic number, because the mean of its divisors is an integer number (4718800).

Almost surely, 2^18863281 is an apocalyptic number.

It is an amenable number.

18863281 is a deficient number, since it is larger than the sum of its proper divisors (11919).

18863281 is a wasteful number, since it uses less digits than its factorization.

18863281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11918.

The product of its digits is 18432, while the sum is 37.

The square root of 18863281 is about 4343.1878844922. The cubic root of 18863281 is about 266.1985863240.

The spelling of 18863281 in words is "eighteen million, eight hundred sixty-three thousand, two hundred eighty-one".