20247909 has 8 divisors (see below), whose sum is σ = 29451552. Its totient is φ = 12271440.

The previous prime is 20247907. The next prime is 20247947. The reversal of 20247909 is 90974202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20247909 - 2¹ = 20247907 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 613573 = 20247909 / (2 + 0 + 2 + 4 + 7 + 9 + 0 + 9).

It is a self number, because there is not a number n which added to its sum of digits gives 20247909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20247907) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306754 + ... + 306819.

It is an arithmetic number, because the mean of its divisors is an integer number (3681444).

Almost surely, 2^20247909 is an apocalyptic number.

It is an amenable number.

20247909 is a deficient number, since it is larger than the sum of its proper divisors (9203643).

20247909 is a wasteful number, since it uses less digits than its factorization.

20247909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613587.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 20247909 is about 4499.7676606687. The cubic root of 20247909 is about 272.5587068756.

Adding to 20247909 its reverse (90974202), we get a palindrome (111222111).

The spelling of 20247909 in words is "twenty million, two hundred forty-seven thousand, nine hundred nine".