20717239 has 4 divisors (see below), whose sum is σ = 21807640. Its totient is φ = 19626840.

The previous prime is 20717231. The next prime is 20717251. The reversal of 20717239 is 93271702.

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 20717239 - 2³ = 20717231 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20717239.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20717231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545172 + ... + 545209.

It is an arithmetic number, because the mean of its divisors is an integer number (5451910).

Almost surely, 2^20717239 is an apocalyptic number.

20717239 is a deficient number, since it is larger than the sum of its proper divisors (1090401).

20717239 is a wasteful number, since it uses less digits than its factorization.

20717239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1090400.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 20717239 is about 4551.6193821540. The cubic root of 20717239 is about 274.6485383363.

It can be divided in two parts, 207172 and 39, that multiplied together give a palindrome (8079708).

The spelling of 20717239 in words is "twenty million, seven hundred seventeen thousand, two hundred thirty-nine".