21871715 has 8 divisors (see below), whose sum is σ = 26479008. Its totient is φ = 17342080.

The previous prime is 21871667. The next prime is 21871721. The reversal of 21871715 is 51717812.

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

It is not a de Polignac number, because 21871715 - 2¹⁴ = 21855331 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18791 + ... + 19920.

It is an arithmetic number, because the mean of its divisors is an integer number (3309876).

Almost surely, 2^21871715 is an apocalyptic number.

21871715 is a deficient number, since it is larger than the sum of its proper divisors (4607293).

21871715 is a wasteful number, since it uses less digits than its factorization.

21871715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38829.

The product of its digits is 3920, while the sum is 32.

The square root of 21871715 is about 4676.7205390102. The cubic root of 21871715 is about 279.6582352265.

The spelling of 21871715 in words is "twenty-one million, eight hundred seventy-one thousand, seven hundred fifteen".