20717871 has 16 divisors (see below), whose sum is σ = 29237760. Its totient is φ = 13022240.

The previous prime is 20717869. The next prime is 20717897. The reversal of 20717871 is 17871702.

It is a cyclic number.

It is not a de Polignac number, because 20717871 - 2¹ = 20717869 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20717171) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2785 + ... + 7013.

It is an arithmetic number, because the mean of its divisors is an integer number (1827360).

Almost surely, 2^20717871 is an apocalyptic number.

20717871 is a deficient number, since it is larger than the sum of its proper divisors (8519889).

20717871 is a wasteful number, since it uses less digits than its factorization.

20717871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4326.

The product of its (nonzero) digits is 5488, while the sum is 33.

The square root of 20717871 is about 4551.6888074648. The cubic root of 20717871 is about 274.6513311169.

The spelling of 20717871 in words is "twenty million, seven hundred seventeen thousand, eight hundred seventy-one".