21713871 has 8 divisors (see below), whose sum is σ = 28984320. Its totient is φ = 14459672.

The previous prime is 21713849. The next prime is 21713873. The reversal of 21713871 is 17831712.

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

It is a cyclic number.

It is not a de Polignac number, because 21713871 - 2⁶ = 21713807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21713873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 495 + ... + 6608.

It is an arithmetic number, because the mean of its divisors is an integer number (3623040).

Almost surely, 2^21713871 is an apocalyptic number.

21713871 is a deficient number, since it is larger than the sum of its proper divisors (7270449).

21713871 is a wasteful number, since it uses less digits than its factorization.

21713871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8125.

The product of its digits is 2352, while the sum is 30.

The square root of 21713871 is about 4659.8144812857. The cubic root of 21713871 is about 278.9838636111.

The spelling of 21713871 in words is "twenty-one million, seven hundred thirteen thousand, eight hundred seventy-one".