21716858 has 8 divisors (see below), whose sum is σ = 32665152. Its totient is φ = 10828476.

The previous prime is 21716857. The next prime is 21716861. The reversal of 21716858 is 85861712.

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

It is not an unprimeable number, because it can be changed into a prime (21716857) 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, 14060 + ... + 15527.

It is an arithmetic number, because the mean of its divisors is an integer number (4083144).

Almost surely, 2^21716858 is an apocalyptic number.

21716858 is a deficient number, since it is larger than the sum of its proper divisors (10948294).

21716858 is a wasteful number, since it uses less digits than its factorization.

21716858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29956.

The product of its digits is 26880, while the sum is 38.

The square root of 21716858 is about 4660.1349765860. The cubic root of 21716858 is about 278.9966555356.

The spelling of 21716858 in words is "twenty-one million, seven hundred sixteen thousand, eight hundred fifty-eight".