20709218 has 8 divisors (see below), whose sum is σ = 31457280. Its totient is φ = 10223460.

The previous prime is 20709217. The next prime is 20709239. The reversal of 20709218 is 81290702.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (20709211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65378 + ... + 65693.

It is an arithmetic number, because the mean of its divisors is an integer number (3932160).

Almost surely, 2^20709218 is an apocalyptic number.

20709218 is a deficient number, since it is larger than the sum of its proper divisors (10748062).

20709218 is a wasteful number, since it uses less digits than its factorization.

20709218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131152.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20709218 is about 4550.7381818777. The cubic root of 20709218 is about 274.6130889489.

The spelling of 20709218 in words is "twenty million, seven hundred nine thousand, two hundred eighteen".