20718239 has 8 divisors (see below), whose sum is σ = 21683040. Its totient is φ = 19758816.

The previous prime is 20718233. The next prime is 20718241. The reversal of 20718239 is 93281702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20718239 is a prime.

It is a super-2 number, since 2×20718239² = 858490854522242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20718233) 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 7 ways as a sum of consecutive naturals, for example, 7997 + ... + 10265.

It is an arithmetic number, because the mean of its divisors is an integer number (2710380).

Almost surely, 2^20718239 is an apocalyptic number.

20718239 is a deficient number, since it is larger than the sum of its proper divisors (964801).

20718239 is a wasteful number, since it uses less digits than its factorization.

20718239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2689.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 20718239 is about 4551.7292318415. The cubic root of 20718239 is about 274.6529572668.

The spelling of 20718239 in words is "twenty million, seven hundred eighteen thousand, two hundred thirty-nine".