20917871 has 8 divisors (see below), whose sum is σ = 23852304. Its totient is φ = 18172800.

The previous prime is 20917861. The next prime is 20917873. The reversal of 20917871 is 17871902.

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-20917871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20917873) 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 7 ways as a sum of consecutive naturals, for example, 47105 + ... + 47546.

It is an arithmetic number, because the mean of its divisors is an integer number (2981538).

Almost surely, 2^20917871 is an apocalyptic number.

20917871 is a deficient number, since it is larger than the sum of its proper divisors (2934433).

20917871 is a wasteful number, since it uses less digits than its factorization.

20917871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94681.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 20917871 is about 4573.6059078150. The cubic root of 20917871 is about 275.5322847575.

The spelling of 20917871 in words is "twenty million, nine hundred seventeen thousand, eight hundred seventy-one".