18642247 has 4 divisors (see below), whose sum is σ = 20076280. Its totient is φ = 17208216.

The previous prime is 18642227. The next prime is 18642269. The reversal of 18642247 is 74224681.

It is a happy number.

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 18642247 - 2¹⁹ = 18117959 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 (18642227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 716997 + ... + 717022.

It is an arithmetic number, because the mean of its divisors is an integer number (5019070).

Almost surely, 2^18642247 is an apocalyptic number.

18642247 is a deficient number, since it is larger than the sum of its proper divisors (1434033).

18642247 is a wasteful number, since it uses less digits than its factorization.

18642247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1434032.

The product of its digits is 21504, while the sum is 34.

The square root of 18642247 is about 4317.6668468051. Note that the first 3 decimals coincide. The cubic root of 18642247 is about 265.1547547493.

The spelling of 18642247 in words is "eighteen million, six hundred forty-two thousand, two hundred forty-seven".