20817071 has 4 divisors (see below), whose sum is σ = 22709544. Its totient is φ = 18924600.

The previous prime is 20817059. The next prime is 20817077. The reversal of 20817071 is 17071802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20817071 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20817071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20817077) 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, 946220 + ... + 946241.

It is an arithmetic number, because the mean of its divisors is an integer number (5677386).

Almost surely, 2^20817071 is an apocalyptic number.

20817071 is a deficient number, since it is larger than the sum of its proper divisors (1892473).

20817071 is a wasteful number, since it uses less digits than its factorization.

20817071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1892472.

The product of its (nonzero) digits is 784, while the sum is 26.

The square root of 20817071 is about 4562.5728487335. The cubic root of 20817071 is about 275.0889893819.

Adding to 20817071 its reverse (17071802), we get a palindrome (37888873).

The spelling of 20817071 in words is "twenty million, eight hundred seventeen thousand, seventy-one".