18681347 has 4 divisors (see below), whose sum is σ = 18998040. Its totient is φ = 18364656.

The previous prime is 18681343. The next prime is 18681349. The reversal of 18681347 is 74318681.

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

It is a cyclic number.

It is not a de Polignac number, because 18681347 - 2² = 18681343 is a prime.

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 18681347.

It is not an unprimeable number, because it can be changed into a prime (18681343) 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, 158258 + ... + 158375.

It is an arithmetic number, because the mean of its divisors is an integer number (4749510).

Almost surely, 2^18681347 is an apocalyptic number.

18681347 is a deficient number, since it is larger than the sum of its proper divisors (316693).

18681347 is an equidigital number, since it uses as much as digits as its factorization.

18681347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316692.

The product of its digits is 32256, while the sum is 38.

The square root of 18681347 is about 4322.1923835017. The cubic root of 18681347 is about 265.3400026451.

The spelling of 18681347 in words is "eighteen million, six hundred eighty-one thousand, three hundred forty-seven".