21716206 has 4 divisors (see below), whose sum is σ = 32574312. Its totient is φ = 10858102.

The previous prime is 21716159. The next prime is 21716237. The reversal of 21716206 is 60261712.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5429050 + ... + 5429053.

It is an arithmetic number, because the mean of its divisors is an integer number (8143578).

Almost surely, 2^21716206 is an apocalyptic number.

21716206 is a deficient number, since it is larger than the sum of its proper divisors (10858106).

21716206 is a wasteful number, since it uses less digits than its factorization.

21716206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10858105.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21716206 is about 4660.0650210056. The cubic root of 21716206 is about 278.9938634245.

Adding to 21716206 its reverse (60261712), we get a palindrome (81977918).

The spelling of 21716206 in words is "twenty-one million, seven hundred sixteen thousand, two hundred six".