18287947 has 4 divisors (see below), whose sum is σ = 18519520. Its totient is φ = 18056376.

The previous prime is 18287933. The next prime is 18287957. The reversal of 18287947 is 74978281.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18287947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18287897 and 18287906.

It is not an unprimeable number, because it can be changed into a prime (18287957) 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, 115668 + ... + 115825.

It is an arithmetic number, because the mean of its divisors is an integer number (4629880).

Almost surely, 2^18287947 is an apocalyptic number.

18287947 is a deficient number, since it is larger than the sum of its proper divisors (231573).

18287947 is an equidigital number, since it uses as much as digits as its factorization.

18287947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231572.

The product of its digits is 225792, while the sum is 46.

The square root of 18287947 is about 4276.4409267521. The cubic root of 18287947 is about 263.4642246617.

The spelling of 18287947 in words is "eighteen million, two hundred eighty-seven thousand, nine hundred forty-seven".