20718245 has 8 divisors (see below), whose sum is σ = 24900216. Its totient is φ = 16549056.

The previous prime is 20718241. The next prime is 20718259. The reversal of 20718245 is 54281702.

It can be written as a sum of positive squares in 4 ways, for example, as 10484644 + 10233601 = 3238^2 + 3199^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20718245 - 2² = 20718241 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 (20718241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 839 + ... + 6491.

It is an arithmetic number, because the mean of its divisors is an integer number (3112527).

Almost surely, 2^20718245 is an apocalyptic number.

It is an amenable number.

20718245 is a deficient number, since it is larger than the sum of its proper divisors (4181971).

20718245 is an equidigital number, since it uses as much as digits as its factorization.

20718245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6391.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 20718245 is about 4551.7298909316. The cubic root of 20718245 is about 274.6529837799.

Adding to 20718245 its reverse (54281702), we get a palindrome (74999947).

The spelling of 20718245 in words is "twenty million, seven hundred eighteen thousand, two hundred forty-five".