21716855 has 8 divisors (see below), whose sum is σ = 26178432. Its totient is φ = 17294688.

The previous prime is 21716831. The next prime is 21716857. The reversal of 21716855 is 55861712.

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 21716855 - 2¹⁸ = 21454711 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 (21716857) 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, 8624 + ... + 10853.

It is an arithmetic number, because the mean of its divisors is an integer number (3272304).

Almost surely, 2^21716855 is an apocalyptic number.

21716855 is a deficient number, since it is larger than the sum of its proper divisors (4461577).

21716855 is a wasteful number, since it uses less digits than its factorization.

21716855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19705.

The product of its digits is 16800, while the sum is 35.

The square root of 21716855 is about 4660.1346547069. The cubic root of 21716855 is about 278.9966426886.

The spelling of 21716855 in words is "twenty-one million, seven hundred sixteen thousand, eight hundred fifty-five".